https://www.fullbucket.de/music/freqshifter.html

V2.X.X Compatibility: Works on Vegas 20-23 Natively
V1.X.X Compatibility: https://jimmyhogs.com/programs/VSTs/~32-bit_Bypass_Vegas_20-23~/

One more thing, here are the .fxp version file compatibility reports

Export on Old Version, test.fxp can be used on old and new version
Export on New Version, test.fxp can be only be used on new version