That is correct
https://support.microsoft.com/en-gb/help/4027577/windows-change-your-browser-home-page
you are, I suspect not typing the correct URL
If you want Google
https://www.google.co.uk/
or if you are not in UK
https://www.google.com/
after doing so, you close edge and reopen it.
If it still not saving then I suspect your AV in use is not Defender the included AV with 10 and whatever you are using is preventing the change of the Home page.
https://support.microsoft.com/en-gb/help/4027577/windows-change-your-browser-home-page
you are, I suspect not typing the correct URL
If you want Google
https://www.google.co.uk/
or if you are not in UK
https://www.google.com/
after doing so, you close edge and reopen it.
If it still not saving then I suspect your AV in use is not Defender the included AV with 10 and whatever you are using is preventing the change of the Home page.