IMHO, the only exception to 'Change even one poly breaks everything', in this case texture maps, may be the mega-OBJ ports by prolific Richard Mandel aka 'Digital Explorations'. He found a work-flow to concatenate sub-objects' OBJs so each vertex set began afresh within the mega-file. You could copy/paste them out, they'd call their mapped textures and work !!

Vertex lists and counts re-start for each of the many sub-objects, so keeping their number lengths short. Even allowing for those sub-objects' modest admin overheads, this significantly reduces the over-all file size compared to equivalent 'monolithic' OBJ with vertex count rising to tens of thousands, each count-digit yet-another file-byte...

I have asked him to consider doing a tutorial on crafting such 'concatenated' OBJs, he's yet to reply...

Note: IIRC, RM no longer posts DLs, has 'pulled' prior freebies from eg SCG & DA, leaving only their renders. Luckily, I'd grabbed the dozen GB of his team's RE scene recreations...