There is an Fdroid app "Casio G-Shock Smart Sync" Not sure if it supports now but most likely may support in future.

This is an unofficial app for Casio G-Shock, Edifice, and Pro Trek watches. It allows you to control your watch, sync data, and configure settings without a Casio ID. It offers a faster, privacy-focused, and more powerful alternative to the official Casio app.

Key Features check ------------------ - No Account Required: Skip the Casio ID login entirely.

From https://fdroid.gitlab.io/jekyll-fdroid/packages/org.avmedia....