Hello, thanks for your purchases.
Regarding that compatibility, you can see it working in our preview site:
https://www.okler.net/previews/porto/9.0.0/feature-admin-forms-advanced.html
That’s Porto Front-End(Bootstrap 5) using Porto Admin (Boostrap 4) – The main difference are the css classes that are a little bit different (see this post: https://www.geeksforgeeks.org/difference-between-bootstrap-4-and-bootstrap-5/ ).
We will update Porto Admin in the future with more features and compatibility to Bootstrap 5.
If we can be of any further assistance do not hesitate to contact us. We are always glad to help!
Jonas