FWIW Blender 5.1.2 (i.e. the latest one) can import and export DirectX .x files using an addon you can download from[0] (from inside Blender itself).

Though i'd stick with Blender 2.79b for such projects because Blender 2.8 (i think) switched to a PBR pipeline that looks "wrong" when targeting non-PBR renderers (in theory you can recreate the original shading using material nodes or whatever they're called, but setting up materials in modern Blender is already more involved than Blender 2.79b without taking nodes into account). Most of the tools you'd need for making game assets (mesh editing and UV editing primarily) haven't changed much anyway to the point where you can follow most Blender mesh editing tutorials with it :-P. I'm in a few retro gamedev Discord channels and apparently i'm not the only one using 2.79b because of the changes in 2.8+.

[0] https://extensions.blender.org/add-ons/io-directx-x/?utm_sou...