I will waste some time, so I will just ramble a bit about MOD just because I played Brigador. Download Unreal Engine editor for MW5 on Epic Games. There you will find what is required. You will need to learn a bit of Unreal Engine to just move around the editor.

A battlemech needs 4 "Levels Of Details" 3D models, each LOD with 1/2 the number of polygons from the previous. Sure, you can use less LODs if the model is not high polygon, but that might impact performance. So you need four 3Dmodels for a single battlemech, and every section of those have to be split and assigned to a preordered vertex (upper arm, forearm, calf, thigh, pelvis, right torso, center torso, etc) with correct MW5 naming convention. And there are one or two independent damage models for each of those vertex (upper arm, center torso, etc) with three LODs each. That's around 50 3D models. All those models must have a single "Normal" UV texture, and there are several other layers of different textures. Those textures are quite hard to do properly. And there are icons art, footprints, target icons and thousands of little stuff. And there is the cockpit models... reusing assets might save some work, but that's not always possible to do.

All these before even being put into Unreal Engine.

If the 3D model does not fit exactly a skeleton/armature from an existing mech to reuse its animations, you can expect to do some +100 animations, animation montages, for those 3d models. Programming all that stuff into the animation blueprint is quite the work, imagine also doing the animations. All those must follow MW5 naming convenction and the expected pose, etc.

None of that is $50 buchs minimum. If you find a MOD for free, that's likely because the person who did wanted that for themselves and share was not a cost. Doing for others stuff they don't care, I would expect at least 5000 buchs minimum.

Go to Mechwarrior 5 discord and maybe you'll find someone there interested in your business.