Performance hit if I create multiple DBs on same instance

Hi:

11.3 on linux

I've come up with a plan to archive data from my main DB which involves
creating other DBs on the same server. But even though there will be zero
activity on the archive DBs in terms of insert/update/delete, and almost no
activity in terms of select, I'm still worried that the mere existence of
these other DBs will steal resources away from the instance and degrade
performance in my main DB. So my question is whether or not that worry is
valid or not.

Thanks in Advance for any help !