Raian are you saying i have to have Google Play Services, along with Google Play installed
Sorry, I should have been more clear. I believe the notifications work so long as you have Google Play Store/Services installed, you might need to actually open the Play Store to initiate the background stuff but you won't need to log in (accounts are only for actually installing apps from the Store). Make sure to allow unrestricted battery to Google Play Services as described here.
do i need to download my Proton apps from Google Play
No. I have ProtonMail installed from Github via Obtainium and I still get notifications because of Google Play being installed. The only thing I can think off the top of my head that might prevent notifications is having the apps installed before Google Play, as that often causes apps to not realise that Play is installed. This could be per-app, I can't say for certain if thats the case for Proton apps. A simple reinstall of the Proton apps after Google Play will be enough, if thats the case.
And then in order to seperate the profiles, you're suggesting to create another "dummy" google account for use in the profile i'll use for let's say Google Maps.
Only if you're using Google Play to install any apps. I should have said in my initial comment that using separate accounts is only needed if you're actually using them, otherwise simply initiating Google Play and not logging in will work as stated before.