is there a better solution to rw access to system in big sur?

is there an actual way to mount the system volume as r/w? method described here doesn't actually give r/w access, and requires a restart. sometimes i like to make quick mods to the system, and a restart is unconventional. plus, an app i carried over from my catalina install that i no longer need, managed to get into the system volume, and now i can't delete it. is there a better way?