The problem is you left the cat for 5 days, 2 1/2 days is the absolute max!
I had a cat that shit in my bathtub. I finally figured it wanted to live outside like when I found it.
The cat should have shit in the tub, I would have been happy!!
I had a cat who pooped in the tub until I switched to a different litter.
Turned out, she liked the sandy or rounded pebble style of scoopable litter. Hated the jagged edged crystals that were so great against urine odor.
Once I gave in (grrrrrrr) I didn’t have to clean turds out of the tub. I reckon you could say she trained me well, LOL.