Create a filter using a current user

I have a field where i define the user (linked to other schema) and it show the email. I want to use this field for comparing with the user online and only show their data (same user)

I just want to summarize here, what we discussed in the email.
You have to use ‘where’ condition in the role, at the schema level.

Links are a little tricky to query in user rights. I prefer the way when you use a calculated field to “calculate” the email. Then you can use it as a usual text field in user rights (and it is much faster than filtering by links). I usually mark this field as not “Show in grid” and not “Show in edit form” in the Advanced settings of the schema item.