I tried to install diferent stores like aurora or huawei to check for diferent apps, and I would like to know if I should update from those two stores considering that the main app store doesnt have them like Magic Earth, Telegram (not foss on that stores), pdf viewer and microG.
MagicEarth you can try via Aurora, but in most cases it will fail. Because it is a system app.
All system apps, you can’t update via any store. eOS has made some code changes so the signature isn’t the same as in the stores. You best, you will put all system app on the blacklist