Apparently Telegram has two multi-user concepts: groups and channels. Groups are conversations between multiple users. Channels are one-way communications from the administrators to the members of the channel. Channel members cannot create content in the channel.
If you use groups, you run the risk that a bad-actor member will start posting NSFW content that is outside the stated charter for your group. Your group can end up getting limited or cancelled by Telegram. Unless someone wants a significant administrative burden, groups are problematic.
Channels have an option to be private and have the administrators manually add and delete members. There is a URL that can be used to auto-join the channel, but there is always the option to simply never distribute that URL. So channels can be limited to whichever members the model wants there. So for a model with limited time and desire to administer things, channels look like a better fit for distributing content.
Channels have an option to create a discussion group. Those would have the same problems as a Telegram group.
Telegram apparently just tries to follow the law, broadly across many jurisdictions. So if content in your private channel violates no laws, and you act in good faith belief that your channel members are age-verified, you probably will not get the kind of tight censorship that is so common on platforms like Instagram. Telegram apparently allows NSFW content in public channels, and therefore certainly allows such content in private channels.