Most portfolio apps want a login, then they store your bags on their servers. Some want KYC. A few are one slip from being a wallet.
CryptoHODL is a tracker only. No seed. No login. No cloud. Your holdings never leave the iPhone. Prices from CoinGecko.
Free for 4 coins. Pro is £9.99 once. No subscription.
https://apps.apple.com/gb/app/cryptohodl/id6762301572
Happy to answer how the no-backend bit works.
Privacy-focused crypto tracking is an interesting engineering challenge because useful portfolio data often requires collecting information that can reveal a user's activity. A strong architecture should minimize data collection, avoid unnecessary wallet-to-identity linkage, protect sensitive data at rest and in transit, and make privacy assumptions explicit. Combining useful analytics with privacy-by-design principles can make Web3 tools much more trustworthy.