for various reasons i have two routers. (In fact, one is a FritzBox hosting various SmartHome stuff, another is a Speedport from Telekom Germany, that also does the Internet Connection)
The WiFi on the FritzBox is also a lot better and right now i don't have any need to get anything better (all that matters has Rj45 anyway).
This however also is an issue, because i can't easily host something. I have however a Hetzern Server as well and i have tried some zerotier, but i have failed to set it up correctly. Is there an easier way or has anyone something like an How-To for this that works?
Do either routers support going into what's called an AP access mode instead of router? If they do then you could put one into access point mode and run a patch cable between the two.
No WRT for either of them and yes, it does support AP Access Mode, but i don't want to put them in to it, beacuse i actually want the networks to be separate
So you probably won't be able to without a router that is capable of supporting VLANs (not just vlan tagging). If you aren't looking to spend any extra money and have an old computer lying around you could look at getting a multi port network card and running pFsense/OPNSense as an inexpensive alternative.
your secondary router should have an option for change the mode to "bridge mode" in this way doesnt create any problems for create your self-hosted system so take a look in your secondary router configuration,almost all TP-Link Routers have that choice
I don't really understand the problem here. Do these routers each have their own internet connection? Why can't you just attach whatever device you are using to host stuff to one of them, configure your router for port forwarding, and be done? To get a domain name for free, you can use https://www.noip.com/.
If that mysteriously doesn't work, you might want to investigate if your internet provider uses CGNAT (mine does). In that case, you might be able to contact them so they'll turn it off for you. I don't know about Germany, but in Austria they have to comply with your request, by law.
If you can't do that or don't want to expose your device to the internet directly, you have other options depending on whether you want your stuff to be public or not. For private services setting up WireGuard using wg-quick (on your Hetzner server) is really easy, reliable, and very secure. For public stuff, you might want to look at one of the services listed here. I recommend Cloudflare Tunnel, though it's only meant for web stuff, no gameservers etc.
Feel free to ask for more help if you need more details.
The basic gist of it is, Telekom switches back to DSL only, if it detects VPN traffic. And that’s only 2 Mbit/s upload. However, with the 5G Hybrid and SSL Connections on Port 443 i do get the full 60-90 Mbit/s upload. I could just put the Telekom router in my “main” network and have it be the Gateway, but that doesn’t go well with some devices i have.
I don't really want to host stuff, i'm fine with having to make a connection (like WireGuard or a VPN), but if i do it directly, i only get DSL Speeds, because WireGuard is also "detected" now. Everything that's not Port 443 or Port 80 get's routed over DSL...
This however also is an issue, because i can’t easily host something.
Why not? Or rather, to which router do your servers connect, the FB or the Speedport? Or because you're on DS-lite or CG-NAT and don't have a "direct" external IP?
The Speedport via 5G Hybrid. Neither DS-Lite nor CG-NAT. I have a direct tunnel exit IP, which i could also use as external, but i do want to have two different networks, however i want to tunnel from the FB Network to an external exit point (like the Hetzner router)
Zerotier apparently can do that, i have not been able to set it up though. The connection works, but for whatever reason i can't really get any incoming Data to be routed back to the corresponding server.