I would ask him why. When he says “I don’t want to go!” You could say “You don’t want to go. What’s making you feel that way?”
Sometimes kids escalate because they want to be heard. Instead of saying “but you like it when you’re there”, you could say “you don’t want to go” (or echoing whatever he says) so he feels listened to.
It’s like if I told my husband “I’m tired,” and he said back “how can you be? You had tonnes of sleep!” I’d insist that I’m tired (and feel annoyed). But if my husband said, “Yeah, you’re tired today,” I’d feel listened to. If that makes sense?
But it might be that nursery isn’t right for him. If that’s the case, what about a nanny or a nanny share? They’re about the same price as day nursery where I live.
And one thing that helped my DC (who loved nursery but never wanted to go in the morning and still struggles with transitions) was both listening (the echoing back what he said trick) and showing him photos and videos taken there the day before. It worked to motivate him every time.
But if listening / showing photos doesn’t work, and he doesn’t get better, it might be time to start looking into nannies / nanny shares?