When Valravn fought mc he was already very weak but still strong enough to at least require a level 3 because Cole was fighting him (mc was able to do this at level 2 thanks to a perfect matchup against Valravn). So if he were able to escape, I don't have too many doubts that he could devour level 1-2 rookie superhumans or those who arent fighter type to regain a lot of strength and then escape if something that he cant handle shows up, because like you said, it would be far too long for him to play hide and seek.
He won't escape just to fight Mc, we agree on that. (if mc side with Ella , he could fight Valravn to steal is heart to give him to her? or simply to get it and devour it so that she can't get it. )
This is how I see it:
Cole like always takes credit for the things he didn't do. Valravn required Ella, not a level 3. Valravn is a special case among monsters. When he gets injured, he loses power and true to his carrion nature he gains it back by consuming hearts (or something else, but he has a preference for them as it seems).
I think Valravn's timeline looks something like this:
1. Valravn is one of the Chosen S Class monsters with pure connections. He has a special heart that Ella wants.
2. She sends the kids to steal Valravn's heart, probably having hatched a plan first to do it easily and without a fight.
3. Valravn is using his heart for something, and he seems to be sleeping. Cole uses this chance to steal it which
weakens Valravn greatly.
4. For some reason Cole fucks up,and a fight ensues between Valravn vs Cole, Charlie, Shen, Zara and Briar.
5. Valravn has protection against mental attacks, so Charlie, Shen and Zara couldn't do anything to him.
6. Ella (level 4 at the time) has to be involved and according to Briar she gets so wounded that she needs his healing.
7. Valravn is beaten to a pulp, and is
extremely weakened and taken to the cave by Ella.
8. Ella releases Valravn to mess with HERO, and he goes on to eat hearts and
regain his strength.
9. Deus for some reason decides to find and
return his heart to him.
10. MC fights and beats Valravn to a pulp.
After Valravn's imprisonement by Ella, he spent weeks regaining his power by eating hearts, and Deus restored what seems to be his true heart. All he managed to do during this time is raise his power to 160~ and be considered a C+ Rank threat by HERO. So it's quite fair to assume that during his imprisonment he barely qualified as a C rank.
After MC doing so much damage to his heart, Bramon torturing him, staying in a suppressive field for months without the nurishment he needs, I'd be surprised if he had the strength to reliably beat level 2s. And even if he can eat a few level 1s or the weaker level 2s, I doubt he will restore enough strength to do anything more than flee.