Is possible un multi company satup after login select company dialog box

After logging in, the user can select the company, and the selected company will be displayed in the navigation bar. Only data related to the selected company will be shown.
after login show a dialog box to select the company

Please check this.

is possible after login select the company dialog box dynamic
and select company in navbar

No, you have to set it manually.

Otherwise, set the company default using the user permission, but you have to apply lots of permissions. So the best way is to use the session default.

session company shoe w in nav bar is possible

No,

it is available in a user profile and you can easily set.