Thoughts on a mini-split for supplemental AC and Heat in Chicago?

I bought an older house a few years back and while the house technically has central air, somehow they neglected to put in any returns on the second floor, so while there are supplies, the hot and cold air does not appropriately cycle for its designated season. We’ve been running a portable AC unit in our primary bedroom (because a window unit won’t fit) and a window unit in the second bedroom but have to rely on a space heater during the day and oodles of blankets at night in the winter. We had an hvac guy come out to quote putting in some ductwork (back in 2021) and at that time it was already $10k and we would lose lots of closet space on 2 floors. I’ve been thinking about whether a mini split with two zones makes sense for us. It wouldn’t be our primary cooling/heating but could be a real godsend in those two rooms, especially while sleeping (we tend to spend more time during the day on the first floor).

Thoughts? Recommended units or installers?