This is like my expertise - free or cheap unprofessional "system" for running events ahha! Or even just running a group without paying someone thousands to tailor a program ;/
These have worked for me for both online and offline events with hundreds of people involved. I didn't get points for being flashy but I always got complimented on how streamlined/efficient it was. I'll list ones I think will better suit for this type of event tho. Sorry in advance if I patronise you but will just list everything to be safe! I will send you the various links I use (its free stuff like google forms, excel)..
1. Set up a registration form via google forms. It's free and you can make it however you want. The person filling it in just needs the link - they don't even need to sign up to google. Do include a statement of confidentiality at the start and how you will use/not use any information provided.
2. Export it to an online excel (I use google for everything) - it'll update automatically as people submit forms so no need to mess with it. let it update on its own and then you have clean access to everything you need in one place. You can request mandatory information and optional information (like the rider might want to confidentially disclose they have medical issues if say an accident were to happen).
If you are good with excel and even if you aren't (with the power of youtube) can set it up to colour code/notify. ("turn their submission box red if they say YES to "have medical condition")
As for managing the event:
1. Have pc/laptop, mic & headset optional with speakers of course. Check ahead how many monitors your hardware can manage and buy some lonnnnnnggg cables. I had my main monitor/desk setup somewhere cushy and 2 extra monitors 30 meters out in different directions (we put rubber over the cables on the floor). They had to have power over there ofc. I set the two cheapo monitors to duplicate what was on my desktop. I could have a list of timing, notifications, scores etc... nothing fancy. Was just a way where people could go up and see for themselves. If you're worried about thieves or accidents think about how to secure the monitors. We had brackets on a post.
2. Stream. Set up OBS/Twitch and live-stream what is on your desktop. Requires wifi or good data ofc. You are only streaming your desktop as above. You can stream the event with a camera simultaneously too! You could even have two pcs and one dedicated to streaming the ring. You can have a mic and make announcements over it with speakers set up or if people are listening on their phones. Requires only for them to have the link. The app and programs used are ALL FREE.
3. Google/Excel online documents. People don't need to register - they just need the link and a tiny
amount of data. I mostly used this where using wifi was impossible or it wasn't feasible to have a big setup. Quite literally. I had a SEPARATE and PUBLIC excel where people can only view and I was the only one with permission to edit (at my laptop). It auto refreshes. People just need the link ahead of time. We printed and set up reminders everywhere. When people came in we reminded them to check the link for live-updates. Looked like this: example.jpg
Obviously.. you pay someone to update it manually or do it yourself in real time otherwise the entire system is pointless. :P If you're fancy you can make this second excel extract bits of info from the submission forms so you can even do LESS work.
Streaming is the harder one because at a big event unless you have someone sort out the networking side you're just not gonna have the bandwidth to stream reliably unless you have very good data and assuming that your audience has data to watch also. I often used extra monitors, an online excel that I managed in real time and posters or reminding people to follow the link. I liked to save paper so had two HUGE timetables printed and laminated to post up for those that aren't tech savvy. Then they could use the monitors above.
SPEAKERS: if possible I also had a few people whose sole job it was to stand by their speaker (they had a headset) and watch the excel on their phone. When it refreshed and it changed they would call out if someone was done and who was next. I obviously did it myself as well if I wasn't needed elsewhere.
Hope some food for thought. Not quite an app but just as workable.