Interesting question. I think they do. My partner thinks they don't. So lots of opinion and some facts on this!
Those that sell them think they work. Those that sell a competing product think they don't (so check your sources!). At least this place selling them is honest in its appraisal: https://www.footstore.com.au/do-bunion-correctors-work/

At the end of the day, the independent research evidence says that you can improve the ankle of the big toe to improve it by a few degrees after a months wear. That study was done by a university that had no interest in the product.

I also find them useful to help those who have pain deep inside the joint - the bunion corrector kind of manipulates or stretches the joint in such a way that its does help with that pain and the symptoms.

My partner also uses it for that but does not think that they are worth it when surgery can give you a quicker and bugger connection than bunion correctors.

There is no harm in trying them as they are not that expensive.

The bunion corrector night splint worked for me. Fixed the pain in my bunion.