I Have now sorted it. Thank you everyone, for your input and help!

At first, I loaded the VST 3 Plugin and that crashed BIAB.
So, I then excluded the VST 3 Plugin from the listing.
Then I reinstalled Helix Native VST 2.
Then I added the new VST 2 file path in BIAB and did a rescan for the plugin.

At this point I couldn't see the VST 2 in the available plugins list.

Don't know why, but because I excluded the VST 3 from the list, it did not show the VST 2. ???

I had to remove the previous exclusion and now the Helix Native (v3.01) works.