I am one of the biggest Thanos supporters but come on mate, PG Thanos is nowhere near abstract level.
Abstracts like eternity/infinity/death/oblivion are multiversal in power.
Do runes make him more omniscient than multiversal abstracts like death or eternity? If yes, then maybe he can use his "all knowing knowledge" on thanos, but if not, then I doubt he can do anything , because Thanos has gotten around multiversal abstracts without them knowing what he is up to.
Also, even mere champion was able to tap into the power of gem subconsciously, let alone Thanos who perfectly understands the workings and can control the gems fully.
How does Thanos kill what is already dead? He can have all power over physical constructs or beings, but he wouldn't over a character that isn't bound to universal laws like life and death. So this is something that should be thought about carefully. No Thanos can not win, although he would have greater power than RKT, he would not be able to put him down, because he's already dead. Do you get it? However the Rune magic may be able to mess with a creature tethered to the physical plane. The problem comes when people rely on the tiers, and power levels as a means of making decisions, instead of looking at the topic for what it is. Beating RKT with power alone instead of by divine edict would be like defeating Namor and Aquaman with a bucket of water. Thanos simply doesn't have the tools to win this.
Why would power gem negate time stop? It won't. However, a case can be made for Thanos being immune to time stop, as he is outside the order of reality as said by Eternity himself. However, it would be basing this battle on statements, so I won't go there.
But on topic, we do know that power gem has universal+ level of power (atleast in Thanos's hands), and rkt has done nothing to show himself above universal+. So while it is unlikely that rkt will start the fight with a time stop, and also unlikely that time stop of rkt level will even affect Thanos, even if it does, what will rkt do to a universal+ level being in power?
When did they make him omniscient ? Thanos has more substantial experiences than Thor has. Intellect wise with both in the same story Thanos is the brains while Thor is the warrior. This isn't groundbreaking news.
Yes because RKT was outside of those laws. Death ceased to have any meaning to him. The same thing applies to DS Sentry. I'm not arguing that RKT is more powerful than Thanos could become with the PG. I'm saying that fighting RKT would be a lot like us trying to grab a guy made of air. He'd simply have no power over RKT.
It's not that Thor doesn't die, it's that he can resurrect himself. This may or may not count as a forum win, but I don't think people care about a scenario where Thor would endlessly ressurect until he wins via attrition...lol
The reason he died at the end of Ragnarok was because he used all the rune magic to break the cycle.
Death the entity only has power over those that are in line with it's rules. RKT was outside of Death's influence. There are several characters that are outside of Death's influence. It becomes less about the displays of power, when that power is not felt because the other being was completely out of phase with the physical universe. Thor pierced the veil in that story, and once he did, he was no longer affected by the laws of the physical universe, because he had become metaphysical. Thanos would have no power over him, because he wasn't like the rest of the dead, who lay in a helpless state that can be mainipulated and/or called on at any time, but without any power to resist. RKT was autonomous. Check it out. That conversation that was given to Thanos and Adam Warlock by what seemed the almighty indicated where Thanos really measured up overall. RKT's boss is that guy, not Death. Since Thanos would not possess a divine edict, RKT would simply be beyond his grasp. He pulled off an all father's head like a grape. Treated Mangog like he didn't even exist. Rume magic would be beyond Thanos' physical capacity.
Lot's of people tend to get so stuck on the tier systems beyond Superman and those guys, that they refuse to see the truth staring right at them. RKT would obliterate Galactus, for example.
No way does Thanos win this. He doesn't have the authority. Sorry.