I love the idea behind Spaced Repetition, and especially incremental reading. Reading incrementally (https://supermemo.guru/wiki/Incremental_reading) is the best way to retain information and helps you read faster too! I didn't see any app out there that had a modern user interface with good UX (SuperMemo is notorious for it's hard to grok interface). So I made my own https://github.com/melpomenex/incrementum-tauri and demo here: https://readsync.org