An open source alternative is not a clone

The phrase alternative to sets an expectation that the replacement does everything the original did. Almost none of them do, and the ones that try are usually worse than the ones that do not.

What good replacements offer instead is a different shape. A self-hosted analytics tool answers fewer questions than the hosted incumbent and needs no consent banner to do it. An open design tool stores files as SVG and uses CSS layout primitives, which is worse for some workflows and much better for handing work to a developer.

Migrations fail when the trade is not made explicit at the start. Someone adopts the replacement expecting parity, finds a missing feature in week two, and concludes that open source is not ready, when what actually happened is that a different tool was chosen without deciding which of its differences were acceptable.

Read the descriptions here for what a project chose to do differently, not only for what it does. The differences are usually the reason to switch.