Check out “portfolio performance” [0]

It’s a desktop and mobile app that can sync via shared drive like iCloud. AFAIK it encrypts the data by password. Supports for tracking stocks, auto update prices from different providers, multi currency, fees, dividends, etc.

[0] https://www.portfolio-performance.info/en/

Are your positions really that sensitive? A lot of hedge funds don't even care enough to have client-side decryption.