i suspect what you get depends upon the host broadcaster that TNT Sports get their feed from.
TBS has i believe US rights to the Tuesday night game in the regular season and typicaly have a sequence of three programmes , MLB Lead Off (pregame) , the game itself , MLB Closer (postgame). This is the same sequence of programming that TNT SPORTS (UK) use here for that game.
it seems probable that TNT Sports (US) are involved in the production of these programmes and broadcast them also on their HBO Max Us service. So here in the UK TNT Sports appear to have arranged to take the additional pregame and post game programming that TNT Sports (US) have for that game
For other regular season games during the week TNT sports (UK) will take feeds from various host broadcasters . ..ESPN seems to be one for example. So unless TNT SPORTS (UK) has agreed to take further programming from each of the host broadcasters they would simply show the gane itself.
Only my speculative view.
