First, many English-speakers are familiar with -stan, which is used in seven different country names, plus some region names.
https://en.wikipedia.org/wiki/-stan
For most of these, you can get an ethnonym or demonym by removing -stan or -istan.
Second, the -ar in particular has a lot of trouble with non-rhotic English accents, where "Myanmar" might already be pronounced the same as "Myanma"!