Poorly designed, failure-prone, brittle internal tooling was a time and energy sink to the point where even the most trivial deployment change was a nail-biter. Automated tooling and tests that were ostensibly created to make life easier were the number one pain point and constantly failed in obscure ways that required cutting tickets to teams responsible for the automation.
More often than not these tickets would be ignored and issues would persist for weeks beyond what's reasonable.
I'd actually force myself to write even trivial code on weekends to ensure my ability to develop didn't atrophy as a result of lack of use.
That, paired with the awful corporate culture and constant fear of PIP/job loss forced me to finally leave.
Generally a very unpleasant experience all around, sans the compensation and name on the resume.