You did'nt say you were running Native M1 and which OS you use.
Compatibility has been discussed many times in the forums, and there are FAQ articles about it.
I think Arturia can't secure AL4 to run on Silicon MACs in Native mode. (FYI:I'm on Windows.)
Keep in mind, that ALV have your old sounds too, Especially when you enable "Include Legacy Sounds" in ALVs main menu.
Have you tried to replace a AL4 with ALV as a test without saving things before you know it work? The same sounds you have used with AL4 can also be used with ALV.
I also assume you can revert to run none Native M1 mode - Rosetta if needed? You must have run AL4 before. Then you can render your old AL4 projects to audio, in case you can't or wont replace AL4 with ALV.
I understand what you are saying. But at some point any application can get compatibility problems with your OS, CPU or other software. Not only applications from Arturia.
Converting tracks to audio files is the only way to be sure to keep it as original as possible. Even sound engines in DAWs and other soft- and hardware for that matter can change at any time. Also backups are need to secure work.
Good luck.