End-to-end encryption (E2EE) is a security property—only endpoints can read the data. Quantum-safe encryption (QSE/PQC) is about the algorithms you use to keep that property intact against future quantum computers. In practice, the 2026 path is hybrid: keep E2EE, but upgrade the building blocks to post-quantum primitives (e.g., ML-KEM for key exchange, ML-DSA for signatures), alongside today’s ECC/RSA until the ecosystem fully migrates.