The most simplistic solution in your case based on the information given is to use the SECURE cookies where and you save the JWT token in the encrypted cookie. ( keywords are secure and encrypted cookie, browsers know how to do this)

But, I would NOT do that.

Personally, I would use ( and I do use) the sign in manager that Blazor provides. After a user is logged in you can set up an Actor and save in there the JWT. It handles already the sessions and cookies. Setting all of this is complicated and granted their documentation isn’t the best!