Background:
In o365 if you want to ask external users for approval, and use "Approval" action users receive an error message trying to click on Approve or Reject with 403 in the background. You have to use the "Send Email with options" action.
This doesn't track tasks in https://emea.flow.microsoft.com/manage/environments/<tenantGUID>/approvals/received
External users trying to open that link will receive 403.
Side question: Is there a way to somehow track those tasks? (even by adding 5 additional actions)
I am looking for something similar to Workflow History List and Workflow Task List.
Background continued:
I created another Flow environment and can see all of them in the Flow admin center:

External users invited to the non-default flow environment can receive approval emails (not send email with options!) and after clicking on Approve or Reject do not receive error message. They can also navigate to https://emea.flow.microsoft.com/manage/environments/<tenantGUID>/approvals/received.
Seems like a solution?
But nothing happens! After they click on Approve/Reject the users do not receive "Your response has been recorded" confirmation screen and the running Flow does not catch this event. Whenever they click on Sent or History in https://emea.flow.microsoft.com/manage/environments/<tenantGUID>/approvals/received, they are redirected to https://emea.flow.microsoft.com/manage/environments/DEFAULT - <ANOTHERtenantGUID>/approvals/received.
MAIN Question: Is this the expected behaviour? Can a Flow environment be shared between users from different domains? Can I use the environments to somehow see the tasks assigned to all users?