n a south-east London warehouse, Uzoechi Osisioma Emenike, more commonly known as MNEK, is sitting on a bench in a makeshift locker room surrounded by semi-naked men. One particularly muscular individual suggestively adjusts a jockstrap, while another, taller and toned, removes his vest before eyeing MNEK with a loaded gaze. It's a lot of sexual tension for a Tuesday morning. But such is the life of a pop star on the set of a music video.

"It is very gay, you're not wrong there," MNEK says, while getting his makeup done for the shoot. The video being filmed is for the fittingly titled Muscle Marys.., the third single from the 31-year-old south Londoner's second album, Bulldozer!! In one corner of the warehouse, behind a large vanity curtain, a group of dancers are being hosed down while filming a shower scene. The water, a runner has assured me, is warm.

The album is MNEK's first solo record in eight years and its title is confrontational. "As a six-foot-four Black man, I am very conscious of the space I take up," he explains. "I am often trying to squeeze myself down. I mean look at where we are right now …" He gestures at the low-ceilinged room. "Can I stand up straight in this space? But that's the reality of being as large as I am. Bulldozer came about because it's one of those words that I found very triggering. But because of that, it felt like the right title."

No one can argue against MNEK's outsized impact on pop music. He signed his first publishing deal aged just 14, and as a writer-producer has worked with the likes of Beyoncé, Kylie Minogue, Madonna, Christina Aguilera, Little Mix and Flo. His songs – Never Forget You, a duet with Zara Larsson, and Head & Heart, a 2020 collab with DJ Joel Corry – have amassed more than 1bn streams. Earlier this year he was nominated for his second Grammy for Larsson's song Midnight Sun, which he co-wrote and produced.

As a solo artist, however, things haven't always been so big. His debut album, 2018's underrated Language, peaked at No 81. "I lost a lot of confidence after that," he says. "I live every day knowing that most, if not all, of my money is made from being a writer and producer. But my solo music is also something I care about. Still, a lot of the time, I will be the only person vouching for me to make my own music."

The visuals and lyrics of Language were also explicitly queer, with one reviewer at the time suggesting the muted response to the record was a result of homophobia and racism. "When it comes to going to the public with my own music, I am a fat Black gay man. Try and sell that." Still, as an artist, he wanted to be true to who he was. "I feel like [withholding my sexuality] is something that maybe could have benefited me, but now we'll never know. I just didn't want to be on stage singing about girls if it wasn't my truth."

While MNEK says he began working on his second album just after Language came out, his poor mental health, the pandemic and other work commitments left him feeling he couldn't make a coherent record. "I needed to figure out how to get back to the pure desire of wanting to make a project," he says. A separation from his management helped. "It took me back to being 14. I was making music and there were no expectations other than me being excited about it."

That purity of intent paid off. Bulldozer!! is MNEK at the height of his powers: an electric rush of window-rattling grime, Godzilla-sized hooks, cavernous club bangers, oily UK garage and lushly layered harmonies. Sonically, it's his personal and musical identity unapologetically stuffed into a hulking pop beefcake.

Its themes are equally big. Songs such as The Wall!! address pushing through self-doubt ("Six foot four and I still got growing pains," he sings), while both the braggadocious, Channel U-indebted Reverse!! and Dirty Little Secret!!'s stuttering R&B explore encounters with "DL trade" (men who sleep with other men secretly, or on the "down low").

Does he have experience with that community? "I have over the years. It's not my reality right now. But it's complicated. While there is a very rich queer culture within the Black community, there's also a deeper history with homophobia, which starts with colonialism, of course. There are a lot of people who believe in the 'batty man' ideology and that being gay is a sin. Those God-fearing environments create DL people. It's not about shaming anyone. I'm just saying: 'You don't have to drag me into it.'"

There is also a sonic thread MNEK is pulling at, too. "Those songs are influenced by the grime and garage and two-step I grew up listening to," he says. "I consider it dance music, as much as house and disco and all the different things I explore on the record. I wanted to claim some ownership of that."

That has proved harder than anticipated. When he tried to clear a sample of Lethal Bizzle's Pow! for Reverse!!, his request was shut down. "They weren't comfortable with the lyrical content," he says with a sigh. "Even though Pow! is hardly a song about morality, [queerness] is a no-go area in a lot of these communities." Other requests were easier: Lady!! interpolates Geri Halliwell's Bag It Up, with MNEK subverting Ginger Spice's turn-of-the-millennium battle of the sexes into a song that embraces gender fluidity, while Oh No!! All the Boys!! samples the piano riff from the Clash's Rock the Casbah.

Desirability politics, meanwhile, come to the fore on Muscle Marys.., which addresses the toxicity of male body standards in the gay community, something MNEK has experienced first-hand. "There was one instance where I had hooked up with a guy. He was a total Muscle Mary, a quintessential LA gay," he recalls. "I found his Twitter account. It turned out that he had tweeted saying: 'Hey, this British musician is messaging me. I don't think he's that attractive, but should I do it just to say I did it?'"

That's horrible, I say. "It's vile. In those intimate settings, of course there's an element of transaction there, but you want to feel desirable."

Body image is something MNEK has struggled with his entire life. "I've always been fat. It's something that you're dealing with or running away from or keeping a tab on," he says. "But I've taken up the gym, which has become part of the fabric of my life, as far as feeling confident about my body."

Just then, someone comes in to say they're waiting for MNEK to film. The dancers have dried off and the locker room is set up. MNEK jumps up, tugging on a vest, protecting the white fabric from his dyed yellow hair ("It stains everything!"). Despite the simple get-up, he looks ready to be a pop star again. "I wish I hadn't been so hard on myself [before] because I'm really fab and I've done really great things in my life. This time I want to really, really enjoy it."

Bulldozer!! is out now. the UK and Ireland to 15 November; tour starts Bristol.