Open-source website builders

Astro is the most widely deployed of the 3 projects here — static-first framework that ships almost no javascript. The honest answer depends less on features than on operations: the best one is whichever your team will actually keep patched and backed up.

The software is free; running it is not. Budget roughly $5–20 a month for a small server, plus your own time for updates, backups and security patching. You are swapping a subscription for maintenance work, which is a good trade only if someone will actually do the work.

Often yes, with Docker and a managed VPS. Several of these projects also sell a hosted version, which keeps the open-source licence and data-ownership benefits without the maintenance burden — at that point you are comparing their price against the commercial incumbent's.

Widely deployed open-source software is not inherently less secure — the code is inspectable, which is an advantage. The genuine risk is operational: an unpatched self-hosted service facing the internet is far more dangerous than a maintained SaaS product. Security depends on your discipline, not the licence.