Regarding the title of your thread "Anyone have experience with LiFePo4 scooter batteries", yes, there is about a decade or more of collective experience, in many threads around the forum; you can search for them with either the full chemistry name or LFP.
LFP batteries do not by nature have less cells than others.
Large format cell batteries do, and those come in the same chemistries that the multi-tiny-cell packs do.
Large-format batteries come in pouches or bricks/blocks/prismatic types, all of which require compression across the large faces to keep them operating as designed. (there are a number of threads about compression you can look up with details). If the pack you want to buy does not have this, or you cannot see it's interior construction, I would skip that and go to one that does. (no point in asking the sellers about it, it's extremely unlikely they know anything about them, and fairly likely they'll lie and say anything you want to hear to get you to buy something.
They are more suited to many vehicle uses because they don't have nearly as many interconnects, so they have many less chances to fail, but being big blocks they don't fit every application.
Many ads use the same images even when they are not selling the same product, it makes it easier to create the ad, so they just copy what someone else used, even when their products are not the same ones with the same capabilities. So, beware all of the battery ads you see. You can find many posts discussing these problems, along with those of counterfeit cells, packs made of low-quality salvaged cells or even made of recycled garbage cells.
If you poke around, there's various discussions about the different points above with more detail.
Some of them revolve around building your own pack(s) using used EV modules from places like batteryhookup, etc.