This might seem to be 2 tricky questions but I have searched on net but didn't find the exact answer.

I know that we can have Wordpress multisite to handle multiple websites with a single Wordpress account BUT they can be deployed on the same hostname.

Q1) Now, suppose that I create Wordpress websites, for multiple clients, so can I use the same Wordpress account for all the clients, OR do I have to install and create different Wordpress accounts for all the clients on their own respective domain/hostname?

The second question is like a follow-up to Q1.

Q2) The reason I am asking is that suppose I purchased PRO version of Elementor Plugin from my Wordpress account, and use it for all my client websites (on different domains) but by accessing it from one Wordpress account? Or do I have to keep purchasing Pro version for all the different client websites?