Your server for unloading mail via pop3 imap to the client?

Question

gmail

We have our own Nextcloud server. There is Gsuite (with a working domain), the place on which is already running out (buying more disk space is not an option). You need to somehow unload Gsuite so that you can pick up mail from there via pp3 to your server and send it via Gsuite from the same (your) server.
What about Nextcloud? You can install the Mail application on it (unfortunately, all applications work only through imap).
The server picks up mail via pop3 <--> the client picks it up via imap <--> the user sends mail via the client --> the server forwards it --> in Gsuite sends it to the recipient --> .
How to implement this scheme, or advise, please, a simpler scheme?

Answer 1

As a person whose work mail has been lying on a free fifteen-gigabyte Google Suite box for ten years, I declare: if buying another disk is not an option, then the option is to clean the box of all garbage and not to fence bicycles.
Another option is to have your own mail server (the best option, but you will need a person to install and maintain it - this is usually more expensive than buying an additional place).