> Btw I am always liable as electrician (since it is dangerous) and can’t hide behind limited liability company in Germany.

Under some circumstances you can be held liable through a GmbH, but not generally speaking.

> rejecting the option with VAT number

Means you are planning to run a small business (making less than minimum wage on a yearly basis), also you are opting out of Vorsteuerabzug. Anyone that wants to live off their business needs VAT. And that is given by Bundeszentralamt für Steuern and the wait times are often excruciating.