I don't know ?

IDK

Is Harry James the name of the song?

It’s the “Captain America and Peggy Carter’s everlasting love” song.

@Optimusprimebumblebee "Neo Astral-X" 123 According to AverWolf the singer. The song is “It’s Been a Long, Long Time” (really should capitalise and add quotation marks to be honest).

That song has only been used twice

And it's only for Captain America movies plus his the scene in Endgame

So it isn't overused

It's been used twice. Once in The Winter Soldier and then again at the end of Endgame. In TWS, they probably just picked out a song that a man from the 40s would like. It's use in Endgame was a callback to that, and it also fits thematically (Steve and Peggy are finally together after a long, long time)

Technically it was used in Loki, as the main thing heard overlapping the other sounds in the Marvel logo.