In “Infinity War” Red Skull says “lose”, not “sacrifice”. So, if just considering that, Thanos should not have received the Soul Stone. If one is so quick to toss someone off of a cliff in order to attain power, how much did they really love them?
“Intentions”. Both Hawkeye’s and Widow’s are “Noble”, each wants to prevent the others death. Is Thanos’ “Intent” any less “Noble”? In his eyes, no, it is not, he firmly believes that his inevitable “Snap” is for the greater good. Gamora made Quill promise to kill her to prevent Thanos from learning what she knew (the location of the Soul Stone), and though he loved her deeply, he tried to follow through (Thanos used “Reality” to change the blast into bubbles). So, if it’s “for the greater good”, you get a “Love Pass” when killing (I guess).
Regarding Cap returning the Soul Stone, Red Skull had also mentioned that the Stone had its own will/consciousness, which is why it was “hidden” in the first place (and how Skull came to be cursed as it’s eternal “curator”). The Stone heavily valued a singled loved soul, so half of life in the universe would be pretty significant (assuming most are “loved”). It’s power misused/abused, it would yearn for “home”/. Cap could have just called it an Uber, Skull would accept it with open arms (looked like a lonely/desolate place).
The “Infinity Gaunet” comics were released when I was a kid and my buddies and I would race our bikes to the comic book store to get the latest issue, amazing to see it on screen (for the most part). I loved these films. Eager to see what the MCU has for us over the next decade. I wonder if “Black Widow” and “Gaurdians 3” will spin-off/tie in to the next generation of films. Also, I’m hoping GotG3 turns out to be “Asgardians of the Galaxy”. That would be fun.