Not really no.

Rumors are Merc would only join if the engines were adjusted to be closer to what they are used to doing. Now we know they had some tricks up their sleeve with the engines which made them dominate for such a long time.

But realistically, Merc was never going to approve this. Their costs would go up with zero benefit for them.

And Red Bull has the issue they only have the ability to maintain and assemble the Honda engines with their own factory, but can’t develop entire new engines. So to have them have a whole new engine next year is a total no-go.