I can sympathize, but this was always the end deal for cloud SaaS apps. Give em a taste, get em hooked, get years of institutional knowledge and process embedded in the app, refuse to let them export it, and crank the price up.
It's not only guys named Larry who are lawnmowers. Don't stick your hand in. *Own* your shit. Be suspicious of anyone who tries to convince you not to. If it's "easy" it might come back to bite you.
Even if some self-hostable software stack does a rug pull and changes the license, you just don't have to update. You can go log into the database and export to whatever format you want.
replies(8):