Not quite the same, but we do have “andfinally” for quirky and silly news.
https://feddit.uk/c/andfinally
Named after the tendency on TV to put lighthearted news pieces like these at the end, to give people something to smile about after all the depressing stuff.
Exactly this, it’s a within-industry term that has leaked out to members of the public. It simply means “we put a lot of money into this, and we expect to make a lot back (for our investors)”
As for where the ‘A’ terminology came from then that itself is likely a reuse of other entertainment industry terms.
In the old days when you released a record album, you’d put the best tracks on the ‘A’ side and the less popular ones on the ‘B’ side.
Similarly, we talk about ‘A-list’ celebrities abs ‘B-list’ celebrities, and use the term ‘B-movies.’ to denote low budget.
And so what happens wben something gets “bigger and better than A?” Well, you just add more A’s!