Amarthol the best approach when finding apps that don't work using the base setup of the OS is to install sandboxed Play Services instructions for which can be found here:
Once done you can then either install directly from Play Store using a legacy (personal) Google Account or a throwaway account you create, OR you can just add Aurora Store to your arsenal and install it from there. Either way will have Libre 2 detecting the presence of play services on first run.
If the app fails to run or crashes with play services present, move onto opening the 'App Info' pane for the Libre 2 app and toggle on our Exploit Protection Compatibility Mode toggle and try to run again.
If this fails it could then be worth looking into going to SETTINGS>SECURITY and disabling Secure App Spawning and trying again.
In 99.9% of cases this process should provide full app compatibility.
Only apps using full SafetyNet or strict Play Integrity API will not run beyond this and at that point there is nothing further we can do due to the OS not being whitelisted by Google for those services.