Order from JLCPCB for the best price. Included technical drawing for thread tapping.
Some options for bolts:
PEV Dev Extended bolts: https://pevdispensary.com/products/extended-titanium-axle-bolts-for-gt-vesc
ProBolt bolts (Not recommended): https://www.probolt-usa.com/titanium-dualdrive-bolt-m8x1-25mmx50mm-race-spec/
CNC 7075 SF Axle bolts: https://www.printables.com/model/865565-sf-gt-axle-bolts
The author remixed this model.
I added FINS