My advice is to back off a bit till you learn a lot more. ruining a battery poking around or trying to reconfigure it is costly, and stops you from riding. Don't mess around with those little wires, unless you see one broken.
To better carry two batteries, for now, get a good sturdy set of panniers to carry the batteries, and make your rack more sturdy somehow. Get the weight lower. One option that works really good is the cheaper motorcycle bags that look like leather. Another one is ammo boxes as panniers, or metal pannier baskets.
You can make a Y connector to run both batteries together, just make sure both are full and balanced, before you hook them together. You will still have to charge them separately. Just connect the two final power wires coming out to parallel them.
Or just run them one on the way to work, one on the way back.
Balance your packs by letting it sit for half an hour after the green light goes on, then unplug, and re plug to restart the charger. If it does not restart, ride around the block to start it back up. While its sitting, the bms is discharging the higher charge cells, when it starts back up, it will fill the lower charge cells a bit more. if way out of balance, it will take several repeats of this process. No need to manually balance your pack yet. It can be something to learn how to do later though, when the pack is on its last legs and won't balance anymore.
If your pack holds full charge after its unplugged, its balanced. It should be at or close to 54.6v full, and hold at least 54v after you unplug. Any less, it needs to balance more. Running 100% out tends to lead to a need to balance, so the more often you charge, before you are all the way empty, the less it tends to unbalance itself. Charge at work was my solution, most days I used 50% to work downhill, and 75% back home up the hill.
Later on, when you need to replace your batteries, you can get a triangle pack. For now, carry the battery lower, on a rack that does not sway, and it will feel ok to ride it.
Later on maybe, you can get a welder and start rebuilding steel bikes into ones that handle better by lengthening them 6-9 inches so they have wheelbase more similar to motorcycles.
like this one.