dpmeter3 update to 1.3.4 fixes a bug when updating parameters in VST2 version. So now you can use VST2 version. Since the parameters numbers in VST2 version change you have to check a setting in Track Inspector Settings page and restart Track Inspector in order to use the VST2 version parameters. If you install both VST2 and VST3 versions of dpmeter3, then REAPER will probably use VST3 version by default. But you can check in the hidden Track Inspector tracks which plugin is inserting. Since both VST2 and VST3 versions share the same plugin name "dpMeter3 (TBProAudio) (6ch)" you can rename the one that you don't want to use in REAPER FX Browser, so next time it will use the one that is named "dpMeter3 (TBProAudio) (6ch)"

* v1.4pre64 (2019-02-28)
  + Support for dpmeter3 v1.3.4+
  + Support for dpmeter3 VST2 version. (check "Use dpmeter3 VST2 version" in settings page. Restart Track Inspector required after changing this setting.)