I believe weapons should be banned and that crime should not exist in the first place
A car can be used as a weapon as can cleaning products, baseball bats, tire irons, kitchen knives, sharp sticks... etc. If someone wants to purpose something as a weapon, then they will.
Crime is defined by law and law is defined by government and/or society. As long as people exist, crime will exist. It is not sound reasoning to believe "crime should not exist" because if it were made illegal to wear black shoes, crime exists again, and as such it is an impossible standard.
Rather, I accept that crime will always exist in the world as a result, but aspire to a world wherein there is no real need to ban things like guns because no one uses them to harm other people - the same goes for cars, baseball bats, etc.
Banning registered/licensed owners from owning firearms does not do much, because the last thing a potential mass shooter does when obtaining a firearm is register or get a license. As such, laws that ban only really affect people who are generally responsible in the first place.
If all firearms suddenly disappeared, people would just build rudimentary ones if they wanted one for violence. Shinzo Abe was killed by a gun someone built in their home. To prevent that you would have to make the purchase of metal piping and whatnot illegal as well.
Stopping mass shootings, gun violence, and violence in general is not a matter of banning something, it is a matter of education and societal responsibility. Read about the comparatively high gun ownership yet low shootings in Switzerland for example.
https://www.sciencedirect.com/science/article/pii/S1359178924000776