Nextcloud is awesome, you should definitely still use it. It’s really big and has its issues when upgrading, but it’s still one of—if not the—best for file sync and share.
Easy Docker solutions:
My two cents: try it yourself but don’t start using their app store until you’ve gotten a better feel for things. They have some great app store apps, but it makes you dependent on Nextcloud.
But compared to Google and not owning your data? It’s SO much better, not that it’s really a fair comparison.
Sorry your experience has been so bad. I’m using the LinuxServer.io version. I’ve had to run some OCC commands when upgrading and it’s sometimes slow, but for me it syncs my files and does version control + sharing well.