I don't think it's going away, maybe it'll get less feature updates, so if it's working for you I wouldn't worry too much about that (at least for now). But if you still want to switch there are many alternatives - I'm using Bitwarden. It's free and open source and it's been working pretty well for me. As for the migration process, it should be pretty easy, just export your Lockwise data and import it in your manager of choice.
Before Firefox switched to WebExtensions there were addons that made that possible, but I don't think they work anymore. So I have about:profiles page bookmarked which has the restart button and use that when needed. Not the most elegant solution, but it works.