The first time I went to Burma / Myanmar was by accident and I had stupidly wandered into a battleground where the local Shan militia were fighting in resistance to the ruling military junta. I had no visa and wasn't even carrying my passport. When I realized I had accidentally crossed the border from China, I decided this wasn't perhaps the best time to investigate the local fish sauce, so I turned and ran back across the border before either side decided to shoot me as a spy.
A few years later, when the junta relaxed its grip a bit, I returned, this time legally and found ငံပြာရည် (ngan bya yay), Burmese fish sauce. Burmese food instantly became one of my top three favourites.
The sauce was and probably still is very close to the Thai version. In a village near Dawei, I saw boatloads of anchovies being unloaded and driven to a processing plant which I didn't visit but certainly smelled.
Burmese fish sauce is essential in မုန့်ဟင်းခါး (monhinga), a fish soup with noodles, considered by many to be the country's national dish.
Burma Love brand fish sauce is apparently available in the USA from Amazon Prime, but be aware it is made from fish sourced in Vietnam and salt from Thailand. Despite the company's name, their website describes the sauce as Vietnamese.
Burma Love Anchovy Sauce
So far as I can determine Burmese sauce from actual Burma is unavailable, possibly due to sanctions.
Do not confuse Burmese fish sauce and ငါးပိ (ngapi) which is a pungent fermented paste made with fish or shrimp. ငါးပိချက် (ngapi jet) is the most commonly seen.
Ngapi - image my.zegobird.com