I don't think "want" is the term to be used. He lost his memories and he's just not putting up a fight that's why he said "I lived long enough". He thinks the important memories are too much of a burden.
"All I wanted was to hold you, just once..." I also think he wants to sleep with Baron but that is because that's what he wanted to do all this time. I think this will spark memories and we will get flashbacks in between scenes. That's how the author has been doing it this season.
Instead of confusing the readers I think the author wants to keep the suspense until the last chapter this season. That's why she didn't tell MonoBaron's childhood story in straight chapters. Well, in our MonoBaron army there are already the deciphering team so we understand the story and know what are the loose ends that we have to wait for answers.
The sad thing is I think Mono wants to die.. he even said it himself that he lived long enough and I think he wants to at least sleep with Baron before he dies. Or it could even trigger some memories? Also about the "hiding" thing I think that has to do with Mananans dad Baron hiding what he knows about what could have happened to Monday because he probably doesn't want Mananan to be with Monday. And tbh I think the author wants to confuse tf out of everyone so the ending can be a surprise and so ppl can all have different opinions on what they think will happen lol. I know a lot of ppl don't like this story but I love it and I like being confused but also kinda know what's going on xD