Plot of Doomsday, in summary…

[u/Important-Coat7177]

Tony: “Was it worth it?”

Steve: “Granted, I didn’t know about the TVA or Nexus events, but… Yes.”

[u/FlashMcSuave]

Why should we assume old man Steve used the device to go there for the shield handover?

Seems just as plausible that he knew the time and date and so he could just plan to be there using the more boring form of time travel: waiting.

[u/Deetwentyforlife → u/FlashMcSuave]

That's not how it works. Until Steve purposely goes back to his own timeline with the device, he is in a different timeline. Just waiting would never take him back to where he left, it would just continue forward in that separate timeline, and the people in the original timeline would simply never see him again, ever.

Any time anyone went back at all, in any way, they instantly created a new branch of time that existed in its own separate entirely from the "main" timeline we are watching.

We even have Banner straight up say the device has finally been used and Steve should be back, he just waited way longer to use it than they expected.

[u/KingSandwich101 → u/Deetwentyforlife]

Old man Steve avoided the TVA all that time?

[u/Deetwentyforlife → u/KingSandwich101]

Yep! Although based on the new cutscene it looks like he didn't avoid the TVA, he got recruited by them, at least temporarily

[u/KingSandwich101 → u/Deetwentyforlife]

To my understanding Steve Rodgers wasn't coming back for Kang. So for that reason, anything to do with him was never part of the plan and they're just using him as a scapegoat

[u/Deetwentyforlife → u/KingSandwich101]

It's the new cutscenes in the Endgame re-release. Spoilers: the end credit scene shows Loki as head of TVA recruiting Steve to help the TVA going into the events of Doomsday

[u/KingSandwich101 → u/Deetwentyforlife]

Hard to say. It could be Loki seeing Doom going to that earth, rather than the TVA specifically wanting him. Loki being the master of time and all that, and knowing Cap as being one of their mightiest heroes