I see 60cells per pack, assuming 2000mah average it looks like you have aprox 120ah @ 24v pack - which is about 3000watts.
You could start with a cheap BMS ($30) sort of like the meter you show in picture but actually will balance without overheating.. ISDT BattGo BG-8S Battery Meter,
https://www.amazon.com/gp/product/B07797N9BG/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1 This little meter will eventually balance them and will give audio alarm if a pack voltage (settable) goes to low.
A next level (that I purchased) was based on DIY Tech & Repairs youtube - checkout
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When you reach 10-15kwh you'll probably want to go on up to Batrium BMS (or other) will full control. I know its expensive, but as you grow and work with you're project and it gets bigger and bigger it will make more sense!.