Non-existent career progression - impossible to advance, even into positions that are what you're already doing (each job title has two bands - you can try and wrangle a progression into the top band. If you got told you're in the top band? Tough, that's all the progression you can get, even if the next role up is what you're already doing - you can be doing that for years without getting any acknowledgement or pay increase). The only thing you get for long service is 1 or 2 extra days off, not even a gift voucher! The job family structure assumes a pyramid, with lots of lower-ranked workers and a few higher-ranked ones - when the company has mostly mid-rank and above workers, it's not fit for purpose and doesn't work with the skill-mix the company has.
Bad pay, even worse pay increases (sub-inflation for several years, despite taking on multiple new responsibilities), and no relationship between pay and position (the breadth of experience - from a few years to multiple decades - under the same title makes it obvious that "salary" and "position" are entirely unlinked, and an announced pay review has never been finished/released).
Multiple companies awkwardly glued together - you might have to work with multiple, completely unrelated, products, repos, tech-stacks etc., and switch between them several times a day, having to remember all the wriggly differences between them every time. Will you get paid more for this? Of course not, even though it's multiple different roles in one.