Can I legally host my own ultra cycling event as a private organizer?

Hey everyone,

I’m thinking about creating and hosting my own small ultra cycling event. I’d love to know if anyone here has experience with that or knows what the legal situation looks like.

My plan would be:

• I organize the route and logistics myself
• Participants sign up privately (not a big commercial event)
• I would promote it on Instagram or other platforms to find riders
• No profit — just a fee that covers basic costs (e.g., GPS tracking like FollowMyChallenge, essentials only)
• Participants would sign a liability waiver stating they are responsible for themselves

Now my questions:

1. Is it generally possible to organize a private ultra cycling event without being an official company or registered organizer?
2. Can I advertise it publicly (Instagram etc.) without running into legal issues?
3. If participants sign a liability waiver, does that protect me from being responsible for accidents/damage?

I’m based in Germany, in case local laws matter.
I’m not trying to make money... I just want to create a cool endurance challenge for people who are into the same thing.

If you have advice or experience with hosting grassroots endurance events, I’d really appreciate your input!