Thanks, @Terry_Hopper for your help, I really appreciate it.
Just to tie this off for the knowledgebase, and those who get here from Google, rundown on the fixes from Google Forms => Update Notion Database Item.
This Tread gives a pretty good walkthrough of what works from the Notion side, thanks @Simo .
The Fix
There does not seem to be a need to change the data coming out from the Google Form, only in how it is mapped into the “Update A Database Item” individual fields, I wasted a fair bit of time playing around with the Tools, Iterator and Array aggregator.
Notion & Multi-select
As in @Simo answer, there is no need for the join for Notion Multi-Select fields, so below will get you there.
{{map(*foo_array*; "value")}}
Notion & Rich Text Field
@Terry_Hopper answer will get you across the line for Rich Text fields.
{{join(map(*foo_array*; "value");, )}}
Hope this helps, this is a great platform, just needs more info for newbies like myself, and it would be great if we all came back and uploaded the solutions not just run off with the answers.
Cheers
Matoni