Thoughts on locking a toddler in their room during sleep training

We have a very smart and very persistent toddler (turning 3 in Feb) who's going through a major sleep regression. A month ago, she learned to climb out of her crib, and has been routinely holding us up for hours before she goes to bed. We converted her crib to a toddler bed so that if she got out of bed, at least she could get back in. The hold-ups haven't stopped, though. It's a lot of "3 more minutes" or "I need ice" or "I want to read that again."

I've been reading Why is My Child in Charge by Claire Lerner. She suggests placing locks on doors as a way to reinforce boundaries and train kids on staying in their rooms / going to sleep. As in, "from now on we're going to read 3 books, sing a song and hold your hand for 5 minutes, but if you come out of your room after that, we're going to lock the door." The guidance has parents entering the room to respond to some toddler needs (like using the bathroom), and unlocking the door after the child has fallen asleep.

Lerner says over and over in her book that this isn't cruel, that it's actually good, because having fewer choices is easier for kids. They also learn to deal with not getting what they want in a safe environment, which builds resilience. She has case studies where kids get the program within a few days and their parents don't need the locks anymore.

Separately, we've taken an online Big Little Feelings course that doesn't suggest locks, but has parents calmly walking their kids back to their room, saying "sweet dreams" etc. and promptly leaving. I appreciate this approach, but I'm worried our daughter would get addicted to coming out and trying different things with us, or joking around, etc.

Has anyone else tried locks? Have a similar persistent / spirited toddler? Thoughts?