Not true.
Many western countries sell weapons to Myanmar.
Myanmar Armed Forces is using G 120TP aircraft from Germany, AS 365 and EC 120 helicopters from France, Schiebel Camcopter S-100 from Austrian, 76 mm naval guns from Italy, Fokker 70 from Netherlands.Spare parts are also available.
France ATR is also operating a repair and maintenance facility in Myanmar since 2016 and that factory repaired all ATR aircraft from Myanmar including ATR 42 and 72 from MAF as well as those from other countries.
For the US, even if they sell weapons, we can’t afford that much.
However MAF acquired 8 Beechcraft 1900 aircrafts from US between 2015 and 2020.
Myanmar also acquired LPD from Korea. If US interfered the sale, Korea won’t sell it.
US is also accepting a number of Myanmar military officers for training especially in APCSS in Hawaii.
Actually Myanmar is operating more western military hardware than Bangladesh.