Import / export activities (engagements)

Upvoting here. We want to do indepth reporting of Contact activity using Activity Feed data. So preferrablly not only can we export as spreadsheets, we can also call for that info via API.
I understand there is “Engagement” API, but many individual types of “Engagement” don’t have endpoints available. For example, no way to retreive Ad interaction via API; or a lot of 3rd party integrations show up in Activity Feed, but no API to retreive for “per contact” engagement info.
So a catch-all solution is to retreive all Activity Feed data as text, then we clean-up text/do post-processing ourselves.
Would appreciate Hubspot team’s feedback on this. Thanks.