The average SAP internal app is probably worse.

Off the top of my head: workaday

Workday looks horrible but at least it's functional. AI Studio is neither and I get a headache even thinking about using it

ADP: looks like shit and doesn't work. Also, there are apparently no alternatives.

“Myself” is the top nav item to see anything relevant.

Literally every internal IBM tool interface.

Years ago I tried navigating the IBM website to download CPLEX (I think it was freely available for academic use, can't remember). I've forgotten the details now, but I still remember how bloated, slow and just plain bad that site was -- it felt like there were layers of unusability.