SFDC Campaign Member Date for newly synced records to Marketo

We continually sync new records from our SFDC to Marketo and when they are newly created, all their previous campaign membership history is also logged on the date they were synced (regardless of when they actually became a member of that campaign). Marketo confirms that is expected behavior. We want to be able to score people with engagements within the last 30 days (Responded date last 30 days in a marketing SFDC Campaign). Marketo support recommends creating lead/contact fields in SFDC to pass last campaign membership details over and when it syncs to Marketo we could use the data to narrow down last 30 days. However, we sometimes do bulk loads into SFDC Campaigns where a record could be a member of multiple campaigns during that specific load, and we wouldn’t want to overload the feed or cause misalignment between campaign and date updates.

Marketo also confirmed, that Member Date isn’t visible in Marketo or we must know the exact SFDC Campaign (which we don’t always know ahead of time).

Has anyone come across this scenario or have any other options we could use to try to have SFDC Campaign membership and date available post sync to Marketo and we can narrow down the specific membership date in Marketo,