The Filter function in webflow is limited to only filtering by CMS fields without any ability to inject an attribute or "filter for only this user" type fields. I went through all of your guides, forums, memberstack's guides, and jetbrains guides and it seems like doing this is only possible in situations where you pass a static field to filter OR adding massive amounts of complexity for something that would take half a line of code normally.
My personal goal was to create one member dashboard smart enough to understand who is logged in (via memberstack) and simply pass that user information to the filter or some middleware (like airtable) so that you can pull up a basic filtered list to only contain relevant information based on that user's ID or email.
The ultimate goal would be to be able to pass a parameter to a filter, but being able to open that field up as much as possible would be amazing to be able to filter and sort in more intelligent ways.
I feel like this added so much complexity to a step that is so simple that it made me consider moving my project off of Webflow.