I too started with an Anycubic Linear plus. The only original parts on the printer now are the linear rails. I was actually considering putting the leftover parts back together to have a third printer, but then I realized I'd just want to re-upgrade that into a duplicate of my second printer.

eventually I'll get off my butt to machine a replacement.

PRINT a replacement. 🙂

unhappy with the filament extruder drive assembly

Look at Zesty Nimble. High initial cost, but dead reliable.

For your bed issues, I find clamps printed in PETG work quite well up to ~100C.