Have you considered EPax? They sometimes offer refurbs at price points that may fit your budget.

Not sure if all their components are US sourced, but they are US based and offer real customer support.

Maybe you have too much squish?

Wipe down the build plate regularly with IPA to help keep it clean; I do this as part of my pre-print workflow. That and scrubbing the nozzle with a brass wire brush to help keep burnt filament getting into my print.

How hot is your shed? Depending on your shed temp, some filaments actually like it hot. I have a PLA filament that likes to print at 220C and in an ambient enclosure temp of 90F.

If your shed is near 120F-140F, its perfect for ABS/ASA (be mindful of VOCs); maybe consider switching filaments while its hot out - making lemonade out of lemons and all that.

cheers