Our AM setup is rockbound at 6960 unless we hook up a programmer (Stretchy).
Stretchy's programmer can be a little intimidating, I suppose, though I'm sure that he doesn't think that it is. I think that many or most of his customers haven't tried to change frequency.
If you are having trouble or are not touching it out of fear (and I don't fault you for either of these) and want some help, send me a DM and I might be able to help you. I don't know if he's revised his programmer, his header (the connector), or instructions since 2020 though. I know how to use what I have; I can change frequency at will and I even reverse-engineered his hex files to get close to the intended frequency, though still with a small amount of residual drift (that has always been there and I'm not going to try to fix).
His directions that I saw in 2020 are correct but there are probably a few items that need more detail, e.g., a fuller, more detailed explanation of how to connect the programmer to the transmitter. If anybody cares, I can publish more detailed directions than he has provided.