What did you decide to do? I too got an estimate from an HVAC company to install a mini-split of $6K. I had decided to go the Mr Cool DIYroute, but a co-worker of mine dabbled in HVAC when he was in the Coast Guard and actually got his HVAC license a couple of years ago so he could by his own refrigerant (R-22?) and charge his own system when it went down. At the price you can get one of the Pioneer units (~under $700 for a 12K BTU) if you can get someone to help you install it, I figure if it tears up, it is almost replaceable. It's almost a tenth of the cost of a HVAC company, and half the price of a Mr Cool DIY.
7.4.4 Theater Room: JVC-RS500, Silver Ticket AT 2.35:1 142”, Onkyo RZ830, Anthem PVA-7, Panasonic UB420, Apple TV 4K, JBL Studio 530’s, 4 - 15" DIY Sealed Subs
3.1 Living Room: Samsung 64” F8500 Plasma, Anthem MRX 300, Dynaudio Audience 52’s, Dynaudio Audience 122C, NHT SubOne, Roku Express (2019)