i've been thinking about the "i love you"/"i know" scene in star wars in relation to EO which i know makes no sense but
see, my favorite interpretation of that scene is that han's "i know" was to reassure leia. it wasn't cocky. han had never tried to hide his love from leia but she wouldn't let him in, and she wanted him to know, even in his last moments, that she really did love him. and han wanted leia to know, even in his final moments, that she hadn't failed to demonstrate that love.
and i know that the parallel to EO should be obvious bc elliot has straight up said "i love you" and olivia is so emotionally closed off. but like... olivia just saw herself as being so fundamentally unworthy of love for so long.
i think, deep down or maybe not so deep down, elliot knew olivia loved him which is why it was so hard for him. because he loves her and if she didn't love him that is one thing, but there is this giant maybe always hanging over his head because she does love him.
and meanwhile, yes elliot's love for olivia was obvious to anyone with a functioning pair of eyes, but i don't think olivia ever had anyone look at her like that before.
so if anything, elliot says "i love you" and olivia says "i know" because it is an acknowledgement that she recognizes and accepts the love that is being given to her