I’m not 100% sure on this, but there’s a config in the general which tells samba which user to use, if none is defined it uses nobody. I assume that if you change that to the same user you use via SSH it should work.
That being said, what you’re seeing is expected, it’s complaining that you copied files as user A to a public directory and now user B can’t delete them unless user A sets the files as read/write for everyone (chmod) or transfers ownership (chown). There’s a thing called ACL’s that should allow you to set the permissions to the same as the parent folder so you can have everything be 777, but I’ve never used it so can’t really help, however with the name you should be able to find some examples on the internet.