What does your digital UC membership card say: If it says All Access, then you're good. Mine said All Access within a week of the change. I also have the card ytd spend showing.

From the UC website:
United Club cardmembers can unlock All Access membership after reaching Premier Gold Status or by spending $50,000 on purchases each calendar year.

The word 'or' is important. Your MM status makes your spend irrelevant. Also, Gold is Gold regardless of how you earned it and as a Million Miler you earned it.
MM companions did not earn their status, so they are treated a little differently with regard to Plus Points, but all other benefits are theirs to enjoy, including *A lounges and All Access UC membership when they have the Club Card, PP Card or purchased membership.
If they wanted to treat MM Gold status as different in some way, I would expect that their counsel would suggest putting that in the remarks on gaining All Access status and I do not see such a remark on the MM page or in the terms & conditions..