Use those cheapo cakes that make the water blue.
Scrub the bowl clean ... I've used a utility knife blade, on edge, successfully.
Buy a bathroom brush and brush the bowl after every use .. piss too.
The blue stuff and the swish of a bowl brush works wonders.
MY wife taught me all this.
(There is no greater expert on bathrooms than a woman)
A 5 gallon bucket works fine for all human waste. A little sawdust for filler and a compost pile at the corner of the yard and you’re good to go. Literally.