Quercetin on its own is not significantly senolytic. Only in combination with dasatinib. See:

https://doi.org/10.1371/journal.pone.0190374

Another argument against quercetin on its own having any significant effect is that it is widely used in large enough amounts. It would be well known by now if it had significant senolytic effects, because everyone with arthritis would have found their conditions meaningfully improved. That sort of thing doesn't escape notice for long.