To be fair. He's had like no promo and his numbers aren't as bad as most people that have topped charts this year or last year. If you're going to compare him to Adele, then compare everyone to Adele, but it's all pointless in the end.
Yes, we know Adele is like the biggest artist and seller this decade
Also don't think Zayn cares about charts or numbers. That's why he praised that Miley quote so much about already having made enough money and just putting out music he likes