HEVC stands for High Efficiency Video Coding so the “High Efficiency” setting is the correct one.

I think that’s a good idea.

Test out filming in 1080p@30fps and 4k 24@30fps and try to discern if you even see a difference.

I have plenty of space on my iPhone but I still only ever film at 1080p@30fps because it’s already such good quality.

HEVC allows you to save around 40-50% of space compared to the “Most Compatible” mode without losing any quality because it’s a more advanced codec.

Apple’s 1080p in HEVC is extremely high quality and you can record a ton of it.

I’d try it out and compare it to 4K because you might find it to be more than sufficient, and you’ll save a ton on space.