Mmmm, hmmm...meh!
Honda has supplied the whatever RBTH numbers engine to RB this season, so I don't know how good their next engines, Ford is also no newcomer and they've developed this one since 2023, I don't expect anything extra from either of them.
Imho the engine was fine, they gave the engine for many years. Imho there was an aerodynamics issue that they didn't find/understand properly and which was making the cars highly unstable.
Cadillac, Audi....one is a newcomer, a great motorsport team, but still a complete newcomer, the other has a Ferrari engine!
Oh wow. I didn't know.

However, Ferrari engine did interesting surprises too now and then. Not for long time, usually, but you never know. Let's not dismiss them so easily, especially as they were focusing on 2026 car since... way too long actually...
I still think Mercedes will decide the next season, and it's not just their team, they power 3 more teams with their engines, so if they are indeed better than everyone by a huge margin, as the rumors try to spread, you could end with former favorites battling for finishing in points.
Mercedes probably saved some millions with Lewis leaving, they probably used those in the new car, hence an extra advantage there.
And they had stability afaik on the engineers area. Actually they were already boasting a strong engine, didn't they?
On the other hand the aerodynamics also matter hugely, so.. let's see.