How do I get my noise floor to -60db?

The high noise-floor is mainly electrical hiss, rather than audible noise in the booth.

It may be possible to reduce that faint electrical hiss noise by experimenting with the gain (knob) settings on the Yeti mic, & mic gain in Windows audio.

If that does not solve the hiss problem, post-production Noise Reduction will be required.

All Noise-Reduction is not of equal quality: Windows audio < Audacity < store-bought NR plugins.

I also recommend the free version of the Couture expander plugin: it pushes the noise-floor down.
(as with Noise Reduction, just use sufficient to achieve the desired result & no more).

Maybe the chair/booth is making the creaking noises as you move.
A test recording where you move without speaking could help identify where the creaks are coming from.