You should at least play around with the export options and do regular exports. You really don’t want your diary of over 5 years to be stuck in an unmaintained app. And since this seems to be supporting exporting into markdown - maybe try an export and checkout logseq or Obsidian?
TBH: It does sound bad, but it is one of the best ways to lower the effort needed for moderating. Currently every idiot from every instance can show up in your community and start spamming. You have to clean up after you’re back from work and have other things to do. Set a reasonable limit on account age and karma and that will keep the biggest idiots, because they will be banned or downvoted to oblivion before they can start posting in your turf.
They could also give the option to pay for this. They should know what storing a video costs and therefore could give creators the chance to cover that cost.