can you change it so it's clear at first glance it belongs to (old) diablo II ?
something like Diablo 2 Trading Grounds would do it and is much more clear than just "Trading Grounds"

It says "Diablo II" right above as headline. Technically you can post a site suggestion here to discuss or request changes like that, in this case you can probably save your time as it is clear enough and won't happen anyway: https://forums.d2jsp.org/forum.php?f=258

but below its saying "Diablo 2 Discussion" too
by their current design and your logic it should say "Discussion" only (which would be just as confusing!)

Its not confusing at all, a quick glance is all that is needed.

Well some new users may not read that well