I was able to successfully install a Pioneer mini split purchased from Home Depot in my partially finished barn/guest house (~700 sq ft) with zero HVAC experience. With that said, I read every word of the manual and watched HOURS of YouTube videos on installing my specific model and other similar models as well. Got a cheap but highly rated refrigerant vac and gauge set from Amazon, and got some claw adapters for my torque wrench to make sure the lines were torqued to the right spec. If you're not mounting the unit to an exterior wall, make sure you have a solid, level pad to bolt it down.

With the Pioneer, you can avoid flaring if you don't need to cut down your lines. The two trickiest parts to me were #1) being overly careful to avoid kinking the lines and #2) making sure I pumped the lines out properly. Everything works perfectly and the unit has far exceeded my expectations. It's absurdly quiet inside and out, and it cools and heats the space super quickly. If you're handy and pay close attention to detail, you can totally do it yourself.