Cat. 7 network from main house to annex underground

I'm currently not up to date... But could the new WLAN 6 standard possibly also help to avoid wiring here?

Are there already any experiences with that?

For this, WiFi 6 is not necessarily required. WiFi 5 also works, but in the described scenario, I would rather go for a wired solution.

is completely right. Everything except a proper Cat7 ground cable for 5!!!m to the extension is complete nonsense for a private household. If lightning strikes... sorry. I’m not going to build a high-security safe in the basement preventively, just in case I hit the jackpot with a six plus bonus number in the lottery.

I don’t even see the problem in such an absurd proposal being made. But I do see a problem in that when someone disproves this proposal with facts, there is still insistence that it was a good proposal without being able to give even the slightest reason for it. Instead of simply saying 'yeah, it probably doesn’t fit the project that well,' people instead get stubborn or beat around the bush. This not only confuses the OP but also all subsequent forum users with the same question.