Yes both launchers can use proton-ge as a wrapper similar to what steam dose.
As for recommendation, pick what you like. Both programs fill the same function and are both FOSS. Heroic has a nicer interface, Lutris has an option to show logs while you are running a game that can help with debugging if the game doesn't work for some reason.
I'm not sure about digital storage such as cloud serviced. But for example you decide to but a new HDD/SSD you pay an extra 1.25 SEK/GiB up to a maximum of 100 SEK, or a new mobile phone that's another 4.38 SEK/GiB with no upper limit.
The reasoning behind that tax is that in Sweden you are allowed to make personal copies of media you own and apparently the movie/music industry loses to much money due to that law. So that money will go to the movie or music labels as compensation for lost revenue.
Swede here. I would say that piracy had it's peak before the raid in 2006 and further harmed by copyswede and thier lobbying for an extra tax on anything that has some form of storage media, can't remember what year that tax came into effect. I might be wrong but that's my experience.
The only problem I have encountered using installers/repacks with Lutris is that they sometimes can't create the installation folder. Creating it manually in the .wine folder is the only workaround I have found.
Yes both launchers can use proton-ge as a wrapper similar to what steam dose.
As for recommendation, pick what you like. Both programs fill the same function and are both FOSS. Heroic has a nicer interface, Lutris has an option to show logs while you are running a game that can help with debugging if the game doesn't work for some reason.