We actually support two syntax for variables that should be substituted in queries.
This is probably one too much :p
I suggest keeping Jinja only for clarity.
See this code where we already replace the param syntax by jinja: https://github.com/ToucanToco/toucan-connectors/pull/299/files#diff-0f79225d8a2288bbc6507d1647f4e5594e61b8284ca99c89759d678d7f3d3e87R79