From my experience, if you create a mix with AAXDSP plug-ins and then open that session on a native rig the AAXDSP plugins will all open with their corresponding AAX-NATIVE version.
There's no difference between the sound of AAXDSP and native plugins at this time.
Then when you switch back to the HDX rig the plug-ins that you originally instantiated as AAXDSP Will switch back to AAXDSP.
If you create your session and populate it with plug-ins on your native system and then open it on your HDX system, the plug-ins will remain native. You of course can switch the AAX_Native plugins to AAXDSP manually if you own the AAXDSP version, (or use the cool ALT+SHIFT+click that I just learned from diane-son right now!)
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Will Russell
Electric Wilburland Studio
https://linktr.ee/wilburland
M1MAX Mac Studio OS 14.3, PT2023.12.1, HDX, S1/Dock
M1 PRO MacBook Pro OS 14.3, PT2033.12.1, BabyFacePro FS