fwiw this works via curl
curl -H "Content-Type: application/json" -d "{ \"statements\": [ { \"statement\": \"RETURN 1\" } ] }" http://localhost:7474/db/neo4j/tx/commit
and returns
{"results":[{"columns":["1"],"data":[{"row":[1],"meta":[null]}]}],"errors":[],"lastBookmarks":["FB:kcwQwmlUd/XlSAaazhJtAnHT+m+Q"]}
and with Neo4j 5.23