Resolume comes with Alley, a free (as in beer) converter that will convert to DXV3 format, but it only supports input formats that Resolume does. If you install the HAP codec on the computer you get a FOSS codec that works great and is supported by FFMPEG. Works great in Resolume.
Have you considered bone conducting headphones? Since they don't actually cover your ears you stay cool, and if you want to block out outside noise they come with ear plugs. I wear mine constantly.
Shokz OpenMove headphones are around $80 https://amzn.to/3LgYCq8