Appears to be the same as, possibly identical to, the Elefast 73.6V (72V) pack which I have worked with. From what I experienced, I would say it’s optimized for golf carts. The GEM has much greater loads, power needs & consumption and performance demands than golf carts. That battery system uses a 23-cell LFP4 pack and tops out around 83 volts IIRC. The BMS settings are locked from the manufacturer, there is basically nothing you can control or change.
https://www.amazon.com/dp/B0FJSM4465
In fact, check the below linked thread out… actually, belay that, just skip to about post 85. Cliff notes: the OP has an e6, which is the same as an eLXD, they are just set up for 6 passengers rather than cargo. His is modified a bit, it’s on the heavier end, but not much different than your eLXD would be with junk in the bed. He has the same battery you are looking at - and it barely gets to 20 mph and it struggles to go up inclines. That does not seem to jive with what you seem to be looking for.
You don’t want that $1800 Amazon pack. For that kind of underwhelming performance you might as well wait for the 20% coupon sale at O’Reilly Auto and pick up six 31DCM or 31DCMJ group 31 marine 120Ah batteries for $110 each and use the $1000+ you saved to buy something really, really nice for whomever you had to convince that buying this now uber-slug of a GEM was going to be cool, fun and fast…
Being totally honest with you here man…
If you like the load capacity and torque an eLXD has to offer, and you would like to retain that and would like to see 35 mph top end while not sacrificing it’s already slower acceleration further, and your vision of it’s future form which appears to have something like 25" diameter tires… a high voltage battery that can also provide high current on demand, for real, is a good place to start. It will get you a lot closer than anything on Amazon and most other ones being offered up out there.
Neat thing about @Inwo and a battery from him, is that he actually knows GEMs, electricity, motors & batteries and works with others who do too. I’m one of those recovering diverse engineering types, and I wouldn’t have bought two GEMs, multiple batteries and other nifty stuff from over the years if the engineering math didn’t support or I didn’t think he knew what he was doing.