Changing from a double flat pack to a single flat pack is a simple exercise in topology. Making a flat pack into a brick/chocolate bar pack is mo involved and less rewarding.
Converting to a single will look much like this photo:
A brick pack is more dense and connected via welds not solder joints, more like this:
As soon as you have to remove welds and nickel you start to see significant increases in the effort. I wrote up a little walkthrough on recycling cells and though if using all matched cells it simplifies the process a lot - the physical labor needed to clean and prep cells without damaging them is a pain. Cells are cheap enough that it’s hard to justify the effort when i have more money than time.
Last full recycle pack i made took 6months off and on? Was a great learning experience disassembling old and broken packs but it’s lost its novelty and is a chore. Most cheap packs are made the same and break the same ways and the cells aren’t usually up to eskate requirements, only so many power banks and laptops i can reuse them on