Lead acid batteries cannot offer anywhere close to their 20 hour ratings if discharged fast, much less the above 100 hour rating albeit this may be inconsequential due to battery size versus average power consumption. I also wonder about their actual lifecycle performance, but looks like they're still the most affordable technology.
I've already built a few small li-ion batteries with modern 18650 cells (LCO and NMC chemistries), going as far as binning and grouping cells to maximize series pack balance and lowering maximum charge voltage to boost cycle life too. No issues with them, guess it is too early to say anyway.
If you are willing to take a chance with some cells from china the price for li-ion can be lower, although it requires battery pack assembly skills. Take a look at my top choices at this moment:
https://www.aliexpress.com/item/4000197218968.html
This is a cell from a still unknown to me OEM, and rewrapped by some. Here's a review of it: Queen Battery QB26800 6800mAh 20A - the big guy! @ Thunderheart Reviews
By charging that cell to slightly above 3.9V still above 20Wh per can can be extracted at a low C-rate, which is pretty interesting.
https://www.aliexpress.com/item/32795814865.html
As far as I understand this other cell is from Heter, it is used by some Ukrainian fellows in their DIY e-bikes and unorthodox tests. Tester Henrik will soon publish a review (lygte-info.dk).
A problem I face with cell balancing is that commercial balance boards are designed to do it at very high voltage, above maximum permitted voltage. This is not ideal, in my honest opinion. It probably is better to install switchable voltmeters at each battery stage together with pushbutton enabled bleeding resistors (inexpensive flashlights with linear drivers would probably be a nice idea :-D for such role), and do balancing by hand from time to time.
By the way I've noticed that DC solar cable can be somewhat pricey. I wonder if some beefy silicone wire could also do good… 