When can I buy Xbox series X disc from official channels

You have been able to buy Xbox discs from official channels for over 20 years, its entire existence

Buying digital content from a region that is not your region is against the rules & can lead to an account or hardware ban.

As your country is not supported then your only option would be to buy physical copies of games as the Xbox One/Series X are region free when it comes to disc based games.

My Xbox series x 2k24 game won't install and says I have to buy the game for like 30 to 40$ when I have the disc

You have names mixed up. There are no consoles named the Xbox One Series S or Xbox One Series X.

The Xbox One/One S/One X all have a disc drive.

The Xbox One S All Digital Edition does not have a disc drive.

The Xbox Series X has a disc drive.

The Xbox Series S does not have a disc drive.

All the consoles can play backward compatible games. The Series S and One S all digital edition can only play games digitally downloaded.

The other consoles can play games from disc and from digitally downloaded,

I hope this clears things up for you.

see i had bought the lego hobbit video-game on disc last week but when i asked at the cash desk of where i was going to buy it i asked if the game would work on xbox series x and i was told no so i never got it in the end so the disc version of lego the hobbit will work on xbox series x correct ?