the large majority of minisplits are made by just a couple of companies and other companies repackage/rebrand them.

a single air handler/zone/head(whatever you want to call it) will more than likely work just fine for your condo, unless the insulation is super super terrible.

my 1500 sqft house has a 12k btu and 18k btu minisplit, both single zone. both on opposite ends of one another. the 12k unit is in a ~130 sqft bedroom with a door that is left open, and the other unit is in a ~200 sqft bedroom with the connected bathroom always left open and the door to living room always left open.

if both are set to 70 when its 105f outside, the warmest room in the house will be 72-73.

brands don't really matter, there are some models that will put out a good amount of heat into the negatives. but just like central acs; the quality of the install is all that matters. most minisplits are going to do a good amount of heating until about 5f. mine are DIY units that are rated for -5f, and it got down to about 8f this winter. could've been warmer, but the house was kept around 65.