I am quite enthusiastic about ANTLR4 in the F# context.
The ANTLR4 .net runtime (irritatingly labelled "C#" or "Standard") (Antlr4.Runtime.Standard on nuget) works great with F#.
The other great piece of support are Antlr4BuildTasks, also on nuget.
Once you have found and understood all the pieces of the puzzle, it is quite simple, as you can see in this repo. The grammar describes a tiny piece of F#. The parser is automatically rebuilt when you add or change a test.
If you want to quickly try things out, just clone this repo with VS Code DevContainers and run dotnet run --project Test.
For now, I am trying to understand ANTLR and its potential in the context of the F# spec. This might develop into a project to create a F# ANTLR grammar.