Accordion Wall Partition vs Curtain to separate space

I have a long tandem style garage (not mine but long style like this, https://www.garagejournal.com/forum/media/garage-floor-after-pressure-washing.47937/) that I want to section off for extra space as I only have and need 1 car. (note, no approval from city or strata to add a wall with studs/drywall which is why im going this route)

I saw some of those accordion wall partitions (i.e. https://canuckdoorsystems.com/folding-partitions-accordion-doors/) as a pretty good option but it likely would be somewhat pricey. I am curious if just getting a heavy duty curtain would do the trick better for a much cheaper price.

I am not concerned about noise isolation but more so about keeping the space warm as I don't want the cold to seep into the space from the garage side, as well as don't want the heat to seep out too badly. I believe with a curtain there would still be a gap at the top unless I mount the curtains on some sort of ceiling rail.

Any advice or personal experience would be greatly appreciated!