Any downside in using EVE 29V 18650 8.4A, EVE 26V 18650cells, or any of the following batteries for a low budget build?

I realize I probably posted this in the wrong topic earlier, my apologies. I’ve removed it from the other topic and am reposting it here, let me know if this is an issue: Hi, I’m new to building electric skateboards. I’m currently trying to build a board under $500, prioritizing range (at least 20 miles on a full charge), capable of carrying around ~240-250lbs at ~25% hillgrade, with a single, belt driven motor. I also already own a longboard for conversion. I’m struggling to find a suitable battery pack (BMS included), that leaves room in the budget for the purchase of other components of reasonable quality. For this reason, I’ve considered having a custom battery pack made, and have been looking into different cells. I’ve come across these, and was wondering if the price of these cells is in anyway indicative of how useful they would be relative to my goal (20 mile range, ~250lb weight capacity):

EVE 29V 18650 2850mAh 8.4A Cell | $2.35/cell

EVE 26V 18650 2550mAh 7.5A Cell | $1.95/cell

Epoch 25P 18650 2500mAh 20A Cell | $2.75/cell

I’ve done limited calculations, which definitely need verification. Making a pack using the EVE 29V 18650 cells, a 10s5p battery pack could be constructed with around 14250mAh 36V 42A. I understand that the discharge rate may be undesirable.

A 10s5p can also be made using the Epoch having 12500mAh 36V 100A. Both of these packs cost around $120 - 140 based off my calculations (which again need verification). The cost and metrics seem too good to be true. One obvious issue I see with a 10s5p configuration is the size.

Please let me know if there are any suggestions, and if there is something I’m not considering. From what I understand, I’d likely have to purchase a BMS in either case. Making a pack is somewhat undesirable, and am open to limiting the cost of other parts of the build if possible. I understand $500 build with the metrics I’ve specified may be a tall order.