This has been asked and answered umpteen times on the forum.
Admittedly, it’s not included as prominently or explicitly in the pinned guidepost at the top of the forum - although it seems it should be.
Getting classified as professional investor (10 days ago)
Professional Trader Status - Court Cases
Question about Professional trader status Capital gains tax and professional investor status
Considered Professional Trader Status and dividends
Does margin interest rate trading switch you to professional trader? - #6 by 1742
Interactive Brokers, which reports needed for tax declaration? - #23 by nabalzbhf
Taxation of capital gains on option trading - #5 by jay
Article on private vs professional investor
Tax rules for private investors labeled as professional traders
Investing abroad vs Swiss taxes
How to disclose stocks positions to tax authorities
Employer (bank) restricting the use of other brokers
Selling puts on SPY - #2 by San_Francisco
Investing with Robinhood > check with Robintrack.net - #9 by paka
Once and for all:
Occasional purchases and sales of the same stock (or investment fund) within 6 months do not make one a professional trader and do not trigger capital gains tax for Swiss retail investors.