How to film POV with BMPCC6KPro?

I need to film a POV scene in which the arms of the POV person must be seen (he sees his own arms).

Which lens?
Is there a special bracket for the 6K for POV?

Or is there a DIY solution?
I have the Tilta cage.

Lens wise you'll want wide. 16mm being the tightest you'd want to go. A couple options include primes or zooms. 12mm Prime would probably be best. Otherwise you could go with the classic Tokina 11-16mm f/2.8. There's the DZOFilm Pictor 12-25mm T2.8, and the DZOFilm Vespid 12mm or 16mm Primes.

Sounds like you have the Tilta Cage for the P6KPro. Tilta makes a helmet camera rig: https://tilta.com/shop/tilta-hermit-pov-support-system/

I haven't used it myself, but I've seen some good examples online. This would have been a great option had it existed for a feature I worked on back in 2020/2021 period when we were shooting during the pandemic. Would have been great for the soldier body cams footage. Alas, it didn't exist.