I'm thinking of building up a similar battery. In my case, for cold weather starting.
Curious about your long term results. It seems like you used a direct connection to an alternator. I'm curious how that went.
The LTO camping battery has been fine. I just used it about a month ago. I've never tried starting a car with it, though.
I only had it direct-connected to the car during initial testing. Since then I've been using a Meanwell 50a power supply to charge it from the grid, and a Kisae 50a DC/DC charger to charge the battery when off the grid. I'm sure a battery like that would start a car. The Yinlong cells are heavy duty. My main concern is whether the alternator would handle the stress without overheating.
Assuming that the alternator can handle it, I would think it would be alright as long as the voltage is at around 15.5v or lower. I ran into balance issues charging at a higher voltage than that. Most alternators run at 15v or lower. Charging at 14.5v is ok, and at that voltage, you don't really leave that much capacity on the table. As an added bonus, the lower voltage stresses the battery cells less.
About a year ago I added a cheap Renogy battery monitor (the kind that comes with a 500a shunt). That's about the only meaningful change that I've made. If I was building it from scratch today, I'd consider using a JKBMS rather than a simple cell balancer. I don't think JKBMS had anything suitable for this application back in 2019. I won't upgrade now because then I'd have to worry about cooling the BMS...something that wasn't a consideration when I picked the layout/case that I'm using.