Hey @lucas-santosP, I stumbled upon the same issue and could fix it with the comments in this issue: Customize ionic build (e.g. using craco instead of react-scripts) · Issue #4627 · ionic-team/ionic-cli · GitHub
You can just add
"ionic:build": "craco build",
"ionic:serve": "craco start",
to your package.json, to tell ionic cli to use craco for build and start.