Have you considered a mini-split?
https://www.friedrich.com/products/comm ... it-systems
Yes. Expense is high. I'd have to either have a separate condenser unit in the back of the house and tear up a lot of wall and ceiling to run the pipes to the garage, or replace the current central air unit, have only one condenser, and then pay tons more for multiple evaporators and a huge amount of piping runs. No way I'd get approval for even a small condenser unit in the front of the house. It has been considered, much like a tankless water heater but HOA and cost (for air ducting/exhaust) prevented that too.
Next house (retirement house) is going to have a big garage or separate garage/shop building that is climate controlled. I hope...