The moment you sell anything for any reason (rebalance, pay salary dividends etc) the company will owe capital gains tax
You try to take the money out of the company in any way - you will owe personal taxes. At a reduced rate typically, but it’s far from certain that corp+reduced personal taxes would be lower than your ordinary personal taxes if you simply invested everything personally even without considering CGT. And with CGT you’re most likely better off buy&holding personally.
Also note if you will eventually leave Switzerland, the company cannot move with you. The money will stay locked in Switzerland with the company and will incur you extra expenses and risk, such as having to appoint a local director. Or you will have to liquidate it and pay taxes.
Personally I think a company shell could make sense for active prop trading, because as an individual you’re at risk of being labelled a professional trader with different rules of the game and getting slapped with CGT on all your profits and then some. Incorporating eliminates the uncertainly and puts a firm border between taxable investments and CGT-free personal investments. For buy&hold, incorporating makes a lot less sense.
Lastly, consider the value of your time and all the hassle associated with opening and running a company. This is far more than just opening a brokerage account.