Lithium iron phosphate batteries have advantages like being safer and more environmentally friendly. Have you considered using 18650 cells with LFP chemistry in the Open Air Max? You have decided on Samsung INR1860-35E as you have mentioned in AirGradient Forum – Introducing the Open Air Max! (timecode 15m52s)
I understand that they are far less common than NMC/NCA which is the chemistry of basically all 18650 cells.
Noteworthy products that use LFP 18650 cells: MNT Reform