Ok. So are you suggesting that the most practicable alternative is to be a slave to [list of 100+ other vendors]? Going out of your way to defenestrate a trillion dollar technology vendor is a bit bananas to me. If you are trying to run a business, I think you are completely fucking yourself over with this sort of attitude.
How much business convenience are you willing to squander over these principles? And, are you truly upholding your principles on a consistent basis or is this a reductive "at least it's not Microsoft" line of thinking? Microsoft is a big place. Some parts good some parts bad. You may be leaving a lot of upside on the table by never considering them as an option.
We are a "Microsoft shop", but we still use other vendors when it makes sense. I don't trip over myself trying to get 100% off AWS over some ridiculous tribalism. Their domain registration and S3 object stores work really well for us so we continue to use them, even when it creates a bit of integration overhead (SCIM identity sync w/ AAD, etc).