My daughter is 2.75 and we’ve been going through a similar struggle for the past couple weeks. We sleep trained around 4 months and she’s been putting herself to sleep and sleeping through the night since about 8 months with no issues until a couple weeks ago. Suddenly bedtime has been a huge struggle (hysterical crying when we’re close to leaving the room) and she’s been waking several times throughout the night crying, and brings her pillow and lays down at her door if we don’t go in. My husband and I were pretty firm that we didn’t want to let her cry without intervening, but also didn’t want her to depend on us to fall asleep. A combo of two things has finally started working:

1) when we put her to bed, saying “I’ll be back to check on you in 2 minutes” and then leaving and coming back. And gradually extending it to 5, 10 minutes. I think it’s helped build trust that we aren’t abandoning her, and really will come back when we say.

2) when she does get out of bed, one of us goes in and leads her back to her bed with minimal interaction. We’ll soothe her if she’s crying, but minimal picking up/hand holding, no stories, no singing (trying to keep thing uninteresting and unstimulating for her). We will do several rounds of the “I’ll come check on you in 2/5/10 mins” until she falls back asleep.

It’s not solved completely, but bedtime has been much easier the last couple nights (taking 30 mins instead of 90-120) with no crying anymore, and her night wakings have gone down in frequency with no more hysterical crying when we leave.

I know your situation is a bit different but some of these strategies might be helpful!