Do you have a net/cyber cafe? Can you take a USB 3 external enclosure and login to Steam (Make sure you have MFA/Steam Guard), and then restore BG3 through the files you have on your External HDD, and then proceed to let the game update the files on your external enclosure? Just check if they have fast internet. Otherwise if you have a good neighbour that has starlink you can give them the enclosure and ask them to download the files for you.
Alternatively you can buy the Console version. However you would still need to download the Patch 7 files which are coming out in October 2024. Once done you can put Steam to offline mode and Steam will no longer require any internet and BG3 will run just fine (After you have signed into your Larian account for the first time to link it). Turn off Gameplay stats, and Multiplayer.
