I use the Mr. Heater propane cooker heater I used to use in my ice fishing hut in my garage (no longer ice fish). It's this model: https://www.amazon.com/Mr-Heater-F24...94010723&psc=1

Not fancy, but it does the job.

I have it aimed towards where my wife sits and about 5 ft from her. We usually just use it on the lowest setting to conserve propane. Even though I'm 45 degrees and 5 feet away from the heater I get sufficient heat to be comfortable.

Only a 6' hose but the heater is the full length of the hose away from the 20lb tank and sits on the concrete floor with nothing else near it.

Given that it was considered CO2 safe for a 4'x7'x6.5' nylon ice fishing hut, I figure it's safe for a garage. Been using it for several winters without a problem. The only down side it I look like a meth lab owner when I show up at the propane refill place every 3 weeks with 2 empty tanks to refill.

I also have an 18000 BTU Mr. Heater Big Buddy heater, but I need a filter for it for use with the 20lb propane and sometimes it's a pain to get it started. The other one is simple and reliable.