A couple of suggestions:
1) Check your login items to make sure Bambu isn't there. If it is, remove it. Then reboot. That may help to ensure the program doesn't open upon reboot.
2) Go to
https://forum.bambulab.com/ and ask if there is an uninstaller program. If not, ask them for a complete list of all files that need to be removed to completely uninstall the program (this will probably include files stored in your user Library folder). Better still, you might want to do a Sotlight search, identifying all files that contain "bambu". Then, after excluding the bambu files you personally created, you could list those files/folders in your post, asking someone to confirm that these are the files/folders that need to be removed. If they say yes, do the following:
a) Empty the Trash.
b) Move all those files/folders to the Trash.
c) Leave the Trash alone and use your computer for a few days. If doing so messed up other programs (which seems unlikely), you can simply restore everything back from the Trash and start over again, this time being more careful in what you remove. If you are comfortable that everything is working fine, empty the Trash.