Unofrunately that’s kinda hard. The have essentially a monopoly in Germany, or close to it, so I don’t even regularly see alternatives.

Depending on what application you need it for, and what your own skill level is, there is Mikrotik (Latvia). They make all kinds of network gear, including routers (with and without wifi). But if you need the Cable or DSL modem part, I don’t think they have that. In general, they are more aimed at a professional than a home level equipment. They are vastly more powerful in terms of capability/configuration, but also require a deeper knowledge and are just by default more complex.

So there might just not be “good” alternatives, and at least AVM (the company that makes the Fritz-products) is in fact European/German, which is better than nothing…