Cleaning cache is easy. Open settings for FS24 in Xbox main menu, and click on ‚clear reserved space, ( may even had a similar name, my settings are on German…) when you start the game, it will overwrite. No worries no settings will be lost.
And in my router Inadded these to the DNS v6 server list:
dnsv6: 2606:4700:4700::1111 / 2606:4700:4700::1001
I set the rolling cache in the ingame menu to 64 GB which helped a lot.
After that I could easily start the game and even start a flight.