Notice how han says "WISH you back" not "need" or "want". By using "wish" he isn't putting any weight on the other person, the act to wish involves just the first person, while need or want would've put pressure on the other.
It reminds me of the phrase "you can stay".

Also this "so baby love me again if it's okay" is again cautious about the other person. It's not demanding or asking. It's more of an open invitation & probability. It shows he is available but the action doesn't HAVE to happen - "if it's okay"
The whole song is so thoughtful ;;

Wish you back is not that type of tragic song. Although it is desperate, based on the scenario that your name ended bad so separated forever. But the lyrics aren't agony, need & search for the other person. The lyrics are somehow sad but he accepts the reality. He just wishes.

He doesn't blame and scream at fate, time, universe or something else for his misfortune. I find the mentality of "wish you back" very healthy and good. He accepts the reality and just wishes. He does wait for something which might never come but he realises it might not come.

I haven't seen many songs like this. Most are very tragic, desperate, angry, unrealistic etc etc. I can really call this a "healthy" song. I think the lyrics are worth remembering in similar social situations.

Leaving the link to the song here. It has eng subs for the lyrics, just click on cc and enjoy han jisung's beautiful vocals and genius lyrics for "wish you back"