Your step 2 is not needed AFAIK - I’ve never had to touch this setting in all my years of using Windows and Linux/ROCK.
Your step 3 has succeeded because you’ve turned password-protected sharing off. It appears as though you’ve been using your Microsoft Account (which uses an email address) as the username to access the shared folder on your Windows 10 PC. This often seems not to work properly. Why, I’m not sure.
You could use the name of the local account on your Windows PC instead. Windows 10 installations always set this up and map it to your Microsoft Account.
The local account name is the same as the user folder name. So, for example, if your user folder is at C:\Users\fred - then the local account is fred, and this will be mapped to your Microsoft Account which could be fred.smith@xyz.com. In Roon’s Add Network Share page, you would then use fred and not fred.smith@xyz.com as the username, and use your Microsoft Account password in the Password field.