Spin off: Mini Split recommendations

I got the hybrid solar/grid 24k EG4 unit from signature solar, came with 7 panels outputting up to 3200 watts. It was a diy install and the line sets bolted together. No pump or welding necessary. It has wifi and has been solid. I did have to do a wifi reconnect a few months ago but that was painless. Cost was also around 3200. You can get the non hybrid version that is grid only and has wifi much cheaper. I'm keeping a 2700' barndominium with 60% of that in 10' ceilings and the rest 12' ceilings at 72° You can get wifi remote controls on amazon that duplicates your remote and turns the system on remotely so there's workarounds for non wifi systems. I prefer the wifi as mine tracks solar consumption and grid consumption and pretty much everything else. DIY to me means bolt together line sets.

Following. Would like a DIY model for approx same size, 12,000 BTU unit.

I've installed 3 Daikin units with good luck. I did invest in the proper tools (gauges, micron gauge, valve core tool, flare tool, flare nut torque wrench, vacuum pump) and used flaretite seals for extra protection against flare leaks. You'll also need access (or rent) a N2 bottle for a proper air test.

It's not cheap to get the right tools and do it right but it's not cheap to pay someone who may or may not do it right either.

Lots of detailed installation threads on garage journal forum.

I have had a Mrcool for 5 years with no issue. The lineset runs through my attic and I actually needed an extension as there was no exterior wall. Has been really good so far.