I have the following problem:
My room is too far away from the modem (from Unitymedia), my connection on my PC means and my PS4 is too bad. A router, for example Fritz! Can I not relocate in my apartment, because you would have to connect this with a LAN cable to the modem and that would be very impractical and much too complicated in my apartment. I have also tried with TP-Link D-LAN adapters and this has strangely slowed down the speed of my Internet (do not know if it was explicitly on these devices). Since I no longer work with Wi-Fi or gambling I have researched alternatives from LAN and I'm on a wireless repeater of Fritz! Bumped (1750E). I know that this strengthens my wireless connection, but I still want to connect via ethernet. This repeater also has a LAN port. Can I use the repeater in this case as a router by connecting a LAN splitter to the repeater to then connect my PC and my PS4 there? Or are there better alternatives for my case?
(Connecting a LAN cable to the modem and moving it in the apartment is unfortunately not an option!)
Wait, you're confusing a lot.
Even if you connect your PC to a Wi-Fi access point, it is and will remain a Wi-Fi connection.
Powerlan is extremely unstable and much slower than virtually all other technologies and should only be used in extreme desperation.
When it comes to gaming, a wired connection is the only reasonable option. Followed by a direct Wi-Fi connection, as you currently have. You do not have more options.
Each wireless repeater, if not connected by cable, brings you more speed, but also higher latency. Is everything a give and take.
Is not it worth it to install the repeater via WPS in my room and use it by cable?
No, that's not worth it. It makes no difference if you are now connected directly to the router via Wi-Fi or if the repeater does it for you.
Look at wlan mesh.
https://usefulvid.com/faq-avm-fritzbox-mesh-erklaert-video/
And if I use the repeater without cable? What else does the thing serve for?
The repeater 1750E would only be of use to you if you set it up in the still good wireless range of the WLAN router (which should not be in your room!) And uses it in dual WLAN mode (ie 2.4 GHz and 5 GHz simultaneously ), without dual Wi-Fi, the speed would be halved. Whether Dual-WLAN works with the Unitymedia modem, I can't tell you, if necessary Müsstest Du. A FritzBox 4040 behind the modem switch.
On the 1750E you can of course connect a small Gigabit switch and your devices with LAN cable.
(Connecting a LAN cable to the modem and moving it in the apartment is unfortunately not an option!)
Since you have tried dLan already unsuccessful, and if the vorgenanne scenario is not possible, you must probably change the above "no option". A LAN cable can be laid well, e.g. Ribbon cable - a little effort and you have no more connection problems.