nrf52 - $7 Display - $5 Accel - $3 Pulse ox - $12 Haptic driver - $1 Haptic motor - $1 spi flash - $2 Battery charger - $5 Battery LVC - $2 Battery - $3 Buttons - $3 Passives and such - $10 PCB - $25 Total - $79

Prices from octopart and some quick guessing, shipping not included. PCB would be the first to come down in price with even a small quantity, $25 is probably an underestimation with qty=1. Passives and friends can also go up quickly depending on design. There is also an SMT antenna present that could cost a few bucks.

JLCPCB should still have special offers for 4-layer PCBs up to 50mm tall and wide. It might be that you can get five boards made for less than 10€/$. I’ll check later.

Edit: yes, $2 for five pieces of 6-layer, 1.2mm thickness PCBs with ENIG surface finish. Unbelievable, isn’t it? 4-layer, 0.8mm, are possible for a few dollars more if thickness matters a lot (only leadfree HASL, though).

Creator here, you are not far off. I should share bom with prices, will do that on github.

You can just export the BOM from the KiCad source files. No need to commit what is essentially a build artifact to the source repo ;-)