The Bais Halevy says in his Sefer HaBitachon that many Rofim don’t know what they’re doing, and may often make matters worse. So who are you to trust?
The way I always approached this matter is: I have full Bitachon in the Rebono Shel Olam that the Dr. that I see is a Sheliach from Him, and that what the Dr. says is complete Hashgacha. Who really knows the workings of man? Therefore I acknowledge and accept that my daas is nothing, and that the Rebono Shel Olam will send the appropriate sheliach for my health concerns. I therefore follow what my Dr. says, being boteach that this is what Hashem has decreed for me and it’s for my benefit. This way, I never have to question what my Dr says and as a result I have a lot more menuchas hanefesh that I’m in the right Hands. This method also extends to public knowledge of medicine and vaccines in general. We go basar rov, and are ultimately boteach in Hashem that He is the Rofeh Umirapeh.
About what the Bais Halevy says, the reason for this is because people are too boteach in their own daas, either that the Dr is right or wrong. So Hashem sometimes sends them a little message that they’re relying on the wrong things, and will ultimately realize that Ein Od Milvado.