I only skimmed the thread, so sorry if this has been mentioned already. Something people have reported success with is using a VPN service to connect to boundless. Something like Nord VPN for example. What this does is connects via a different route to the region (routes depend on the ISP of both sides). Once your data is in the region quickly, it’s much easier to connect to a server in the same region. VPN services will do connectivity tests when you select a region so it’s quick and easy.
Regarding the game: it could be fixed for everyone using a game-side tunnel. Basically the user would connect to their local server, and the game service would use a known good route to communicate with the other region, taking user ISP’s international routes out of the equation. I’ve described it more here: Solution for bad lag on some planets
EDIT: I know this has been done for other games. iRacing was doing it for some time. not sure if they still do.