Go will definitely be involved even if he loses badly. And no, if this were a Max Raid it wouldn't just be called a Raid, which is a Go term.
And the speculation about old characters needs to stop if there is no real hint.
Max Raid Battle should be against Gigantamax Pokemon (which only appear in Galar).
In Episode 2, the term Raid Battle appear when a group of trainers battle against Lugia. So, it's pretty likely this term will still be used in this episode