anyone installed sso for both netsuite production and sandbox accounts with Microsoft Entra? Can users easily switch between the two accounts if they have access to both?

Yes, we use NetSuite SSO and users are easily able to switch between Prod and SBX with no issues, the key is that the same SAML file that you get from Microsoft has to be used in both PRod and SBX, they can not be different. I am not sure if I am explaining this correctly, our Network Admin helps me with that part.

thank you @Todd Juenemann! that makes sense

Another key is DO NOT add an account claim in the Entra app setup.