The solution is a bit technical and we hope that it will change for the future Odoo versions.

1/ Go on the Odoo Dashboard (connected as internal user)

a. click right with your mouse

b. go into Inspect

c. go in the tab "Application"

d. open the section "Cookies" on the left hand side and click on the "https://domainname.com"

e. type session_id in the filter bar

f. copy the value of the session_id

2/ Go to the Website App (you will be redirected and disconnected)

a. follow the same process than above then

b. replace the value of the session_id with the one copied

c. press enter

d. close the window

e. refresh your page

Let the magic happen and you will access the edit mode ☀️