Just about all these cheaper drop in batteries are built using cylindrical cells, heaps of them all tab spot welded together to form parallel and series connections, much like you see in the lithium power tool batteries. This means lots of little wires soldered to a BMS circuit board that could be 3 layers thick. No guarantee the cells are LiFeP04, quite likely LiPo the same as the power tool batteries because the cells are cheaper and less required. Their cycle life is fraction of LiFep04 cylindrical cells and their cycle life is a fraction of the prismatic cells we use.
I've tested all the likely contenders and nothing comes even close to what we use now, so rather than dropping the quality to compete on price, we will just wait until the sky starts to fall on these cheap drop in batteries.
There is a say attributed to Benjamin Franklin :
The bitterness of poor quality remains long after the sweetness of low price is forgotten.

I guess only time will tell and if people learn by their mistakes and are willing to share their stories about their cheap drop in lithium failures. To date embarrassment seems to prevent people opening up about the bad outcomes and only willing to spout about how great their choice was to buy cheap and how well that choice has worked. As soon as the whole thing goes pear-shaped they clam up.

The OP on this thread has even decided to go backwards to AGM batteries at the moment after a bad outcome with the drop in lithium battery. It is a shame he is not willing to talk about it so others don't fall into the same trap. He does mention in one post " Will try and ressurrect lithium it was bloody expensive" it would be nice to warn others so thet don't suffer the same expensive slug to their wallet. At only 18 mths old I would have thought the 2 yr and 3 yr warranty many sellers are offering would have kicked in, I'm guessing there is a story there as well.

T1 Terry