Getting back into ebiking and my packs are dead

[fitek]

After a very long hiatus and the acquisition of a Shimano EP8 powered class 1 eMTB, I dusted off my 72v folding ebike and the Makita based battery pack is pretty well spent. It has the Shenzen Sucteam controller that was hot stuff on this forum... a decade or more ago. I used Makitas for the packs as there weren't really any good Lipo/Li-ion packs to be had at the time and lead acid was the suck.

I also got my wife a used 36v bike (dead integrated downtube pack, RWD direct drive hub motor) and am putting an OG Bafang bottom bracket drive (which I can't find any specs for, btw) on my cargo bike. The controllers for both are unlabeled.

I'm wondering if y'all have opinions on the most expedient way to get these ebikes running again, mostly on the battery front. I'm willing to swap controllers if it makes my life easier; it sure would be nice to have PAS instead of throttle also.
I've been deep into quadcopters and other RC aircraft the last couple years and have a handful of 6s 5500 mah packs for my cinelifter... built a Li-Ion pack for long range, but it wasn't much fun and I wouldn't want to build a big Li-Ion pack for a bike. I got better stuff to do I've also been eye balling the 56v batteries in my Ego lawn stuff, but it's a weird voltage for ebikes...