Wanda vs Thanos/IG ... hm
Thanos for the slight majority. ... and not because of power output,
since Wanda was every bit the God Thanos became in that perspective,
but because of Thanos' omniscience, & stability with equal capabilities.
They were both all powerful,
but the IG gives the wielder supreme being type status,
where only a direct representation of TOAA's power surpasses it.
Then again, one could surely argue
that Wanda was akin to a supreme being during HOM.
So, while I'll say Thanos takes this,
I could make a valid argument that has Wanda stalemating, and even winning.
Feat wise though Wanda is the superior,
but that's not all it is for me in order to make a sensible decision,
there are other factors that come into play,
and then
after understanding/studying the character fully, the story, the narrations, the Handbooks,
the writer's comments, potentials & reasons why said potentials were held in check,
the power source of the character and type of influence the character has over reality,
and finally the opponents they've beaten.
All that then coupled with whatever feats is how I come to a conclusion.