It's a pity that apart from initially generally denying it, you didn't explain it in more detail again. Because I would also immediately swap the two rooms. How is "guest" used? What is included in "building services"? If guest is used as an office, certainly not late in the evening, the washing machine or dryer runs but right next to the TV already... How often are guests actually there and when are they in the room... probably only for sleeping, right? Please reconsider that.
To be honest, I see no advantage in swapping guest and utility rooms. Yes, the utility room is supposed to have technology plus washing machine/dryer and possibly storage, moreover, the utility room is currently located on the garage side where only a small window is planned. Guest is intended to be used occasionally as an office/home office (with table, computer, printer, shelf), but also overnight accommodation for guests (small fold-out sofa bed if it still fits). We don't have family visits that often but about three times a year for several weeks.