Yep. Though there's also a difference here between "not suitable for youth" and "right-out illegal", and with porn sites that latter one can get problematic because those "I promise I'm 18" banners don't even begin to be enough age auth. OTOH the law only cares about sites actually targeting Germans (as in: They're in German). Things that you won't find on google but aren't illegal as such e.g. include pro-ana forums. Also note that German law makes a difference between erotica and porn, lots of stuff you see on the net would actually be completely fine but the sites don't bother distinguishing.

It's always only DNS blocks, easy to circumvent by setting your dns to 1.1.1.1 (cloudflare) or 8.8.8.8 (google) instead of whatever your ISP configures it to.

As far as porn is concerned, after years of paper shuffling, they managed to block de.xhamster.com (but not any other subdomain), xhamster reacted pretty much within hours by setting up deu.xhamster.com. I kinda expect them to give up. Maybe instead make sure that xhamster.desi is on that search engine blacklist? IP blocks are not an option because overblocking.

kinox.to is blocked because piracy, as well as Russian state media because EU sanctions.