While I don't know the real pay for garbagemen and teachers, often both jobs are Union jobs. Yes, pay for some kinds of shitty jobs is higher than jobs that are more satisfying or are perceived as higher status. One shitty job that does not receive higher pay is harvesting agricultural products. The shortage of workers for those jobs is so bad that we have a special visa program to bring in workers.
I guess we have work arounds and can create incentives to get people to do shitty jobs even with UBI.
Oh, in my town garbage collection is highly mechanized, not a lot of hands on garbage cans, mostly involves driving a truck with robotic features. Not much different that delivering the mail or packages.
TEK