Current Implementation
Currently, the app is available in (Android) Google Play Store and Huawei AppGallery. So-called "degoogled" phones have no "Play Store" or AppGallery access, mostly because they run on modified/unofficial firmware (for example: LineageOS) and/or smartphone owners might not like proprietary software and/or smartphone owners might be banned by Google for any reason.
Suggested Enhancement
I suggest to support inclusion in F-Droid. This requires a build that follows their inclusion policy.
In addition to, or alternatively, I suggest to build an APK and release it here on GitHub (possibly using only free dependencies).
Expected Benefits
Supporting F-Droid and freely available APKs will help the community, as no private company can interfere with the app distribution. Use free libraries means that no bad behaviors can be injected into apps (no tracking, etc).
Alternative Enhancement
If you don't want to support F-Droid or freely available APKs, would you authorize a community-driven fork to access to get.dgc.gov.it APIs?