Map of [Region Name Here]

[octopod]

If you have big mountains on both the east and west of the central realm, you're setting that realm up to be like the Central Valley or the Turpan Basin -- hot, dry, watered by mountain runoff, agriculturally productive? That's pretty cool, I like it, but you'll want to have those rivers flowing south into that bay at the bottom, I think, which will involve removing part of that string of hills down there.

Now knowing that the grey means high mountains, I might connect the grey ridge actually -- erase the bit of it on the southern shore of the inland sea, then attach the northern part with a line going straight north-south across the isthmus to the mountains on the left coast of the southern landmass. Then you could handwave the tectonics by saying that your central realm is a microplate (like Tarim, again!) that's getting squished between the plate containing the southern continent and the inland sea on the bottom + right and the ocean plate on the left, with fairly neutral relations with the plate in the north.

ETA: wheeee, I scribbled on it in crayon

(little S-shaped twiddles indicate arc volcanism; also notice I did the things I described in my second paragraph)