KM The kapton tape I have seen is orange in color so it seems like a sticky/messy way of just using a color filter like photgraphy gels https://www.bhphotovideo.com/c/buy/Lighting-Filters/ci/1329/N/3662541030 or just wearing orange/yellow tinted glasses.
About heat I don't think putting it on the screen would hurt the LEDs as those are around the edge of most panels. I do remember someone taking apart a Kindle and covering the actual frontlight LEDs with kapton tape to make the light less blue. I never saw a follow up to see if that lasted but that's obv entirely diffrent than LCD backlighting.
*Ah didnt seen @daniel_mate's link to kapton sheeting. I think stuff like this is just a cosmetic thing and not really solving any root issues. If you prefer a warmer appearance it can't hurt. I tried uvex glasses which are supposed to be 100% blue light blocking...and are very orange...and they didn't help at all. I also tried tinted and blue light blocking screen protector sheets etc. I fully believe late night blue light can mess with circadian rhythms as evidenced by studies...but I dont believe blue light is a major eye strain root cause.