I really think this more in lines with 4 vs 7
There are some people in the scenario that aren't going to be much help.
Namely Batman is useless in this fight imo.
Namor, Hulk, and Superboy could all lend some kind of help but really are so outclassed or have too little versatility to be factors imo.
That leaves Flash, Superman, the GLS, MM, Supergirl, Wonder Woman vs Strange, Thanos, Mar-vel, and Surfer.
I think Marvel has the biggest guns with Strange and Thanos.
I also think they have the most versatile herald with Surfer.
And team DC does have some people with exploitable weaknesses.
While Wonder Woman could prove a possible hazard for Strange cause of her magic defense which may occupy Strange if Strange doesn't do some hardcore magic stuff.
and Dc does still have numbers though and I could see Superman/Supergirl/Flash giving Thanos a good challenge.
The only thing making this match hard to decide on is Thanos and Strange who could potentially wreck some of these people rather easily if given a chance to.