Little users like you are already using a Lemmy instance as it is configured.
A Lemmy admin can
- block any community they want from showing up on their instance
- block a whole instance from communicating with their instance
- ban every single user as they see fit
Regarding the post you linked above, most of the controls can indeed be disabled, and they are disabled by default: https://piefed.zip/c/fediverse/p/1005977/piefed-admin-settings-that-allow-to-enable-or-disable-content-filters-they-are-disabled-by#post_replies