A site with and app store app can't be totally free speech. You get kicked out of the store. See Minds and GAB for that. Minds now has two apps: One in the store which won't show NSFW postings and one downloadable from their website.
That Parler hasn't been kicked out make me wonder if Parler is a honeypot.
I have to admit that I am not technologically inclined enough to install apps outside of an app store. I'll have to learn that soon though. I'm sure it isn't that tough but just like most people I got sucked into taking the easy route not realizing that exactly what you are saying above is what is almost certainly happening to everything in the app stores.