i am using a Huawei 3372s unlocked version for more than a year now. I am using it in a place that it does not have xDSL or fiber access, but i am getting 50/10Mbps with this dongle. I have a heavy usage on this and it did not fail once.
i got it from ebay but you can easily get it from amazon.de as you asked for. i am giving a link as an example https://www.amazon.de/-/en/Huawei-Unlocked-E3372-LTE-150Mbps-Dongle/dp/B0104LV06M/ref=sr_1_1?crid=23YTJN2NNJJ8L&keywords=huawei+3372s&qid=1649750936&sprefix=huawei+3372s%2Caps%2C116&sr=8-1
Based on your location, there might a provider that offers this usb dongle for a reasonable price.
The dongle comes in 2 versions, software applied.
The s version is simply a usb modem without routing capabilites. You have to find your provider's settings to make a ppp, not that really hard. That means if you have a sim card that offers a public IP, then you are exposed to the public internet and you need a good firewall. There is a downturn on the speed. It gets to a max of down/up 50/10Mbps.
The h version acts like a usb router that does a NAT for you. it means that you get a local IP eg 192.168.1.1 as default gateway. No need for firewall or ppp configuration. You are getting the full speed of the modem, based on your location and provider's limits.
Everything is a matter of configuration for both of the versions. I would not recommend the change from on version to another, by opening the dongle and messing with it.