Say you are taxed 10% on the value of all the stocks you own, this means you have to sell 10% of your stocks annually, and by selling stocks you make those stocks less valuable for everyone… so technically they should be taxed less because value drops down?

Just a note, suggesting a 10% tax is pure fear mongering that billionaires and capitalists use to scare people. The average property tax rate in the United States is 1.1% so that's a reasonable percentage to give. People don't sell 1% of their home every year.

Property taxes are a thing. Stocks are property.