i wish i had an answer but i live with someone that picks up where i fall down for me.
maybe there are some ways you can sort of compromise?
idk the price difference between an auto feeder and self cleaning litter box, but i personally like my feeder (although it was originally purchased because i was out of the house)
and maybe instead of litter you can use another product. i know you can use wood pellets (which i think is typically also cheaper and im probably going to switch back to). but personally what ive been finding best is shredded (news)paper. its not the best for her but its a compromise. its light so not much work. i just throw it out, give it a quick scrub with dish soap and refill it. it seems like more work, but it works while im working on getting better to go back to more proper care, but at least she is getting care.
would disposable ones be cheaper? or would the price add up?
i dont know what kind of place you live in or if you have a veichle or anything, (maybe youll come up with another idea) but what about a long leash and sitting at the door with them? its not a walk, but its some outside time (maybe you already do this considering you said "proper walk")
or maybe theres a park/dog park you can bring them to (maybe at a time theres not many other people)
idk if its much help, but some care is better than no care. and even though externally you dont feel like youre holding up, internally you seem to care about them very much