Syncing the Mail app 'On my Mac' folder between two Macs

Hi

I own two Macs: One MacBookPro and one MacMini. One is in my work office and the other is at home. I sync my work folder with the GoodSync application. The reason why I use the GoodSync application is that I have for 50GB of data and I do not need to have it in the cloud (syncing by two computers is good enough for me).

For cloud storage space reasons, I need to download my IMAP emails on my local computer, once in a while. I have backed up my emails since 2005. They appear in the 'On my Mac' folder in the Mail app. of my MacBookPro, as seen in the figure here.

The emails are located in the Library folder, as per the figure below in my MacBookPro:

Now, I would like to have the same 'On my Mac' folder in my MacMini Mail application. In addition, if I add a new mail folder in the 'On My Mac' folder on my MacBookPro (say for example the 2025 folder), I would like it to be automatically synced on my MacMini.

Is there a way to do that automatically, without having to Export the mail folder on my MacBookPro and then Importing in on my MacMini? Is there a way that when GoodSync syncs the folder in the Library folder that the Mail app. sees the updates automatically?

Can iCloud be used for that (instead of GoodSync)?