I've been in big tech and out of touch with the real world for a while, and I started a project only a couple of weeks ago to get a feel for what the cool kids are doing in web dev in 2024. So I can't claim any deep authority or experience with a lot of different approaches. But I picked Clerk because it was in a tutorial, and so far so good. It couldn't have been much easier, and the free tier seems more than generous enough to get through the prototype stage.
My main concern is that I don't want to weld too much of my design to any one service provider, so I've got to be careful about taking too much advantage of their feature set and API so that it won't be a pain if they go away or it becomes necessary to migrate to something else.