Tesseract OCR is a free open sourced command line OCR built in C++. Its development is paid by Google, but contributions can be made by anyone.
You can use use Tesseract without giving Google anything. If you are very concerned run it on a virtual machine that has no network connection. Personally, it is much easier to set up in Ubuntu "sudo apt install ...
I can suggest you to use the open source GOCR. It may not be powerful than tesseract but you may not have concerns regarding data theft.
gocr is an optical character recognition program that can be used from the command line.