Slack is doing questinonable things anyways. When we migrated away from it to Teams, I wanted to export the workspace to be able to look stuff up in case we need it. We are a very small company and had the smallest plan, no chance, export only with the expensive plan.
Since I'm located in europe, I thought of just doing a data request based on GDPR (at least for my messages). They declined it and referred me to my organization, since we are in charge of fulfilling such requests (how would we even do that if there's no functionality for it?). Absolutely ridiculous.