I am trying to set up rights on a group that will be "project manager" here is the rights I need for this group : 
- View on every project and every tasks
- Edition only on assigned project and it's related task

I already refine the rights to be able to see all the project but editing only the one the project manager is assigned on.

The issue I have is, I cannot set up rights to unable visibility on all task but only unable editing on assigned task. 

If I put those access I can edit every task even the task on project I am not assigned to. And If I remove the write access on task I cannot edit anything 

I tried to setup record rules, I thought the following record rule could help to do what I want but it seems to doesn't work :

I also try to create a new record rule as followed : 

But this lead to a server error on the database.

Is there a mean to set up the rights to be able to view all the task but only edit the assigned one ? 

I am using Odoo 16 

Thanks for your help !