What kind of business do I need?

I have a question about signing up for business.

I'm currently a streamer on Twitch, where I rarely get donations from viewers. There was still no payment from Twitch itself, so I didn't get enough subscriptions / bits.

I also signed up for Fiverr and I'm now earning a little money there, which is not very much at the moment.

I'm also in the process of developing a small game for streamers and maybe offering it on Steam.

At the moment I don't even get a max. 50 euro through these things. But it's more like 10 euro.

The question I'm asking myself now, what kind of business do I need? Can I run it all over one thing?
It may also be that I give up one or the other thing again.

In the game and streaming it is e.g. Not even my intention to make money with it. That would only be a side effect of a hobby.

You have to register a small business as soon as you have earned 1 cent with Twitch

otherwise if you get caught there's a heavy punishment

"With the game and streaming, for example, it is not my intention to make money with it. That would only be a side effect of a hobby."

This argument does not matter to the tax office as soon as you earn 1 cent you want to make a profit and you are obliged to report

I'm also concerned with the example that it is just a hobby, not that this is not a reason not to register, which is why I ask this question at all, but in what context I have to do it, since the profit is not high.

Commercial law knows no allowances. As soon as you start and plan to make a profit, you have to register the business. The trade office doesn't care whether you actually make a profit or a loss later.

And before you expand your business later - with additional fees - register all your plans at once.

Ok, that means I register a small business once, what then?
Are there any monthly things to watch out for?
Or do I just file a tax return every year and that's good?

You can't register a small business because it doesn't exist.
So you register a business. The registration office sends a copy of the registration to the tax office.
The tax office will then send you a questionnaire on tax registration. You can tick the small business regulation (§ 19 UStG). This means you do not have to submit regular VAT returns.
In this questionnaire you must also state the expected profit. If it is low, you do not have to make any advance payments.
You should set aside about 20% of your winnings for any tug-ups.
At the end of the calendar year, you submit a tax return with attachment G and a revenue-surplus invoice. On this basis, any additional payments will then be decided.