@grob @james

Ssh keys are used in place of passwords. One key corresponds to one user. They are more secure than passwords.

Changing ssh the default ssh port from 22 to something else might keep away a few bots but anyone who is actually trying to gain access will just do a port scan to see whats open.

Idk if this helps but maybe it answers your questions?

Best advice I can give is use good passwords. Compartmentalize your identities so very few pieces are connected to each other.