There are probably many ways to spend $5500+ on "upgrading" LP performance on the OP’s Technics 1300G.
I’d go ART 20 and perhaps use the rest in a future upgrade of a next level phonostage.
The ART 20 likely isn’t THAT far off in performance(relative to the OP’s existing hardware) with the ART 1000?
OP’s phonostage is good and gets solid Stereophile review, but we all know there’s always something better. Lejonklou Entity phono preamplifier | Stereophile.com
Once that’s in place, the OP can save for the SP -10-RE-S, a nice arm, THEN get the ART 1000!