Glad to see the restoration worked, I intentionally gave instructions manually via the UI to not scare people off because it involved scripts or complicated sql statements, I'll have a look at adding that query somewhere (it is a wiki post so in theory anyone can edit it but I suspect as you are new it might not let you yet, if it does let you then have at it (if you want)).
It doesn't create a new "sub-profile" on the sync target, each profile is essentially an entire profile in its own right.
So for example I could create have my main personal profile on desktop and make a child work profile but each has its own sync target.
That means I can have another client that only syncs my work profile and another that only syncs my personal profile - they are all independent.
Unfortunately this is where it falls down on OneDrive and Dropbox in particular. It is easy to create your own subfolders on WebDav, NextCloud, Joplin Server etc. to hold your extra profiles (e.g. www.mynextcloud.com/nextcloud/files/Joplin/Personal) but on Dropbox/OneDrive it just puts it into a single folder that can't be changed (as it does it via the API).
I actually made a post about this here - Joplin 2.8 is available! - #10 by Daeraxa