Filter workflows by date completed

I wish there was an option to filter lists by date contact completed workflow, or ‘completed workflow X less than days ago.’

Scenario: we have several lead nurturing workflows which enroll contacts who download various guides, and we don’t want contacts to be active in more than one at a time, since the lead nurture emails essentially call the contact to the same action(s). These workflows are split up into two parts - Part 1 delivers the pdf guide and Part 2 sends a series of follow-up emails containing useful information/resources and CTAs encouraging the contact to call the client or schedule a meeting, etc.

Problem: We need suppression lists which will prevent the contact from enrolling in the Part 2 lead nurturing workflow (let’s call this Workflow X) if they are already active in one of the other LN workflows (we’ll call this Workflow Y). BUT, the only ways I’ve found to achieve this are:

a) create an active suppression list for Workflow Y which includes contacts who are active in Workflow X - problem here is, as soon as the contact completes Workflow X, they are no longer part of the suppression list, and are enrolled into Workflow Y which essentially delivers the same LN emails.

b) create an active suppression list for Workflow Y which includes contacts who are active in or have completed Workflow X - problem here is, they will always be suppressed from Workflow Y, even if it’s a year later when they download a second guide.

It would be great to have the option to ‘refine by date’ for workflows, just like we can with a date picker property value, so I can add the filter: has completed Workflow X les than 60 days ago. This would accomplish my goal and satisfy the client.

And I don’t mean to double up on ideas here, but it would be awesome to filter form submissions that way also. Currently, there’s an option to refine by a specific date, but not ‘X days ago.’