I’m more than happy to just download the installers, and only manually update. That’s how I use to do it when I was using Windows. But the installers don’t run natively on linux, I’m just not sure how best to use them. My first attempt was to use bottles to run an installer, then again to run the game after it installed. That worked - but after doing it once I decided that it would be easier to just install Galaxy instead so that I don’t have to setting things up over and over.
I’m curious about how Steam responds to you adding a non-steam game like that. Are you using innoextract to unpack the files from the installer into some personal directory, and then telling Steam to run the game from there? Or do you tell steam directly to run the installer? … And when you add a non-steam game to steam is that an entirely local thing? (I don’t really want to be reporting to Valve about what GOG games I’m playing.)
I see one advantage of using Steam is that if I already have Steam, then it saves me installing another tool. But some disadvantages is that it presumably won’t do save syncing, or Galaxy achievement tracking - and the installation process for each game might be a bit fiddly by the sounds of it.