Zetos I downloaded the HUD and checked it out, the file is replay/thumbnails/material_bonus. Not on-the-fly for changing colors as you'd want, but yeah. You can export the image with VTFEdit, change it and import it back.
I thank you! It worked. Follow-up question: https://imgur.com/a/HNpBKfr
How do I setup the Match HUD so that even when tf_use_match_hud is set to 1, the timer is the same as 0 (No background rectangle with team colours and win counter)? I'm sorry if the question is vague, wasn't quite sure how to explain what I'm looking for.