Filament runout sensors can be easily DIY'd (endstop switch with a roller in a 3d-printed casing). You'd have to recompile the firmware though so I see how that could be a pain. I wonder why Sovol didn't add one, they're dirt cheap, small and easy to integrate.
Could you elaborate on the SV06's shortcomings? I bought one after selling my Ender 3 (the shittiest machine ever made) and it has everything you want from a home 3D printer. Auto-calibration, no manual bed leveling, an excellent extruder, powder-coated PEI sheet (can print PETG straight on the bed without damaging it) and it's really sturdy. Oh, and it works out of the box (after some quick assembly). It's basically a Prusa without the signature orange and exorbitant pricing. (nothing against Prusa, I love their products, they're just really expensive for the average tinkerer.)