Meta has shown repeatedly that they aren't trustworthy. This is like watching a wolf eat every one of your chickens in the coop and then swearing up and down that if you let it in the hen house, it won't touch the chickens in there. Absolutely zero chance that they aren't going to try to take over and steal data and control it. Why else are they trying to come in? These corporations don't make moves like this unless they see a potential profit. I vote block.
Yet another plug for Calibre. Best I've found for customizing and troubleshooting PDF conversions.