I sympathise with the extortionate cost of replacement batteries - I read recently that the wholesale cost to electric car makers is now around $100/kWh, so to still be asked to pay £1000+/kWh like the new Shimano 630Wh for around £700, is outrageous.
But there is a fundamental principle about safety here, which we all have a citizen's duty to uphold, and actually there is no financial saving buying a battery or battery repair like the one pictured.
The cost might be half, but the cycle life maybe only a tenth.
The way packs like that are assembled is a bunch of secondhand cells - 98 in that case, 14S7P, are each put through a test cycle to measure their capacity at the time of assembly (see the numbers written on the cells) then organised into 14 groups of 7 with similar total capacity, then assembled. That fools the bms and the owner in the short term, I.e the first discharge cycle, but because they are all different ages, different number of cycles, different original capacity etc they degrade at different rates, and very quickly you have a weak cell, and so a weak cell group, and a pile of useless junk.
Hopefully your repair will be done better than that, but if that picture is typical of the repairer's work, I would not hold my breath.