Yeah, if you want to have a master list of games available to install then the purchases have to be under one account.

Otherwise each account will see their own list of available titles, if purchases are arbitrary then these lists may appear random.

I have 99% of my family’s games on my account but have placed titles gifted to or purchased by my 8yo on his account. This isn’t important now while we share a loungeroom and set of consoles but as he grows up we will need to separate our libraries at some point.