It might help if we knew the make and model of your Bluetooth Speaker.
It's pretty unknown from what I can see. After I bought it, it was hard to find. Yafeite brand, model #: K7Apparently, Amazon used to carry the Yafeite K7, but when I search their site today to seek more information it is no longer listed and the only other site I found is in Chinese and located in The People's Republic of China.
No, I do have a microwave but rarely use it except to sterilize things. I also turned off all the other bluetooth devices because sometimes they compete with each other.
That was certainly true in earlier Bluetooth versions but I have not found that to be a problem with the later, low power, Bluetooth protocols not to mention they have much better range.
At this point the only sugestions I can think of are either adding a
Bluetooth range extender or trying a different Bluetooth speaker. FWIW I have been very pleased with an
Anker Soundcore 2. It has enough volume to be heard over the table saw and dust extractor in my shop, runs up to 12 hours on battery or I just leave it attached to an otherwise unused iPhone charger. Sound quality is very good (the bass won't rattle the fillings in your teeth, but you can understand every word when listening to Peter, Paul, & Mary or The Limeliters). To my ears, the sound is competitive with a pair of Apple iPod minis running in stereo and cost ~$170 less.