We had sort of similar at 2 years 10 months
I ended up sitting on the bed with him while he cried for whatever it was, didn't engage in the ask but just said 'it's bedtime, are you ready to get back into bed?'
If he said 'no!' I'd say 'ok, I'm going to sit here until you're ready'. Cue more crying and if wait maybe 2 mins and ask again. When he eventually says yes, I give him cuddle, explain it's bedtime and I'll see him when the owl is awake (gro clock) and then put him back to bed
Honestly it took some time but we were both consistent with this approach and he realised he wasn't going to get what he wanted.
First few nights he'd wake several times and each time would cry for maybe ten mins. Then slowly reduced to one wake and a bit less crying.
Now he mostly sleeps through again and we get maybe once or twice a week he'll wake once but will not protest very much that it's bedtime.
If he ever came into our room, we'd pick him up and take him back and sit on the bed and repeat the above.
Good luck and it hit us by surprise too!!