Do you have to have wall units on that wall? you could go for shelves and avoid the headache. Or maybe you could get a carpenter to box the gap:or build small fake units: Or use some slim cabinets:

Perhaps move the island to the left, so the distance between island and tall units on the left side is about 100 cm and then put something like this over it? You could possibly do that too without moving the island:

Good for you. what's your dilemma?

Something like this but not sure of room dimensions (clearly not as many beds as pictured (!) and i think keeping the ”bed” in the wall colour helps the room feel bigger as in the 2nd pic)