This is all my personal opinion. Others will have a different view on this.
It's a broad subject. To me, it means not trusting the device, user or networking they are using. Zero trust.
You then profile the device, the user, and consider what network they are using to come up with a risk profile, and then grant access based on that.
Because of this, there isn't "one solution". It is a collection of technologies and solutions you form together into a jigsaw puzzle.
This is why when you "Google" the subject, you get broad, vague conceptual responses. It's like asking, "What is wrong with my country?".
Personally, I think Cisco SecureConnect is a great solution for quick broad coverage.
https://documentation.meraki.com/CiscoPlusSecureConnect
Cisco ISE can also be used as another part of the jigsaw puzzle.
Zero Trust also encompasses technologies like XDR, application access, identity management, access management, endpoint patch management, and anything that contributes to or affects the "risk" ("risk" is another word for "Trust").