I had a bunny who would tolerate his collar without a bother (he was a lion head x so his fur acted like a barrier and he didnt feel iton much) he also had a bell attached which he got used to.
The collar was for the purpose of finding him in the house, and alerting people that there was a rabbit about. It was kind of a trade off- I worried about him getting stood on by accident vs the collar getting caught
However, and I cant stress this enough, it isn’t a good idea. There was never any accidents, but my house is open plan and there was never anything to catch a collar on, all the same, once he learned to come when he was called, I abandoned using the collar.
What I would say is maybe not make him free roam all at once. I have a pen set up, that my rabbits go in if they are getting too underfoot, or when I’m asleep, or if Im having people over- I limit the chances of accidents by keeping them in the pen in scenarios where an accident is likely to occur.
So maybe slowly start increasing the amount of time he is allowed out in the living area, this helps people get used to having a rabbit to be mindful of in the room