You seem to be very happy with GOG Galaxy and that's great. I just happen to prefer the offline installer instead. I am not sure what you mean about "offline downloading for nothing", though. When a new patch is released, there is usually also a single (offline) patch file available so the download size should be identical/similar to what's happening via GOG Galaxy. However, in the past, BG3 offline patches were published with a fairly big delay but this has now changed thanks to Jess.
It's a "waste" imo because the newer files always supplant the older in the offline files stack--ie, download an installable this week, next week another patch is released which supplants last week's offline installer, etc., ad infinitum. This will have happened dozens of times before BG3 is finalized. Generally speaking, Galaxy updates quickly and automatically--don't have to keep track of ten million patch-file versions...;) Just open Galaxy and let the game update automatically while you do something else. There will still be delays between the Galaxy release and the offline patch versions in most games, however, with Galaxy being faster. I've 365 GOG games atm--many of them are final and will not be seeing more updates--they are in my personal archives--since I don't like buying games that do not include my very own installable copy. (I have greatly paired down my Steam purchases because of that.) Galaxy is the only way to keep up with that library automatically and without effort. Basically, Gog Galaxy updates installed games just like Steamworks does, with the key difference that Gog also supplies its customers with their own installable copies of their games--which is where Offline comes in. With Gog you get the best of both worlds--but if you don't use Galaxy then you miss half of what Gog gives you. You seem to be thinking that it's an either-or-proposition--that if you use Galaxy you can't use Offline patching--of course that is not true. You can use both! If fact, it is GOG's intention that you do.
I will say that for years I stayed away from Galaxy for the primary reason that Galaxy was still in beta--but the software has been out of beta for years and the new 2.0 versions seem rock solid to me--and work exactly as expected. So I have shed my "fear" of Galaxy these days.
Also, just because you use Galaxy does not mean you have to use the Galaxy UI to run your games. I don't--I run them all from their own executables, exactly like if I'd downloaded and installed from the offline installer. Exactly as I did before Galaxy matured to its present state. No difference--except Galaxy does the housekeeping for me automatically. I would think everyone would know this by now--but some folks don't, as I've discovered.
I allow Galaxy to update my games automatically, but that is as far as I use Galaxy. It's darned convenient.
So...sometime, couple-three years from now, Larian will have executed its last patch for BG3, possibly...;) That is when I'll download the offline installer files, put my copy in mothballs, ...and hope there won't be another Update...! (Knowing Larian, that will be ongoing for a couple of years.)
So, that's it--hope this answers your questions...;) Using both services from GOG--the way you want to use them--is the ticket, seems to me...;)
