This is my general method to find and install apps:
First hit F-Droid
If F-Droid doesn't have it, hit the Play Store through Aurora. Carefully assess each and every candidate returned by the Play Store search by searching for feedback on DDG, as I treat anything served up by Google as adware / spyware even if the Play Store says it's free of ads, doesn't need permissions or it's open source.
If the Play Store doesn't have it (an older version of an APK I specifically need for instance) hit APKPure or Aptoide. Download each promising APK manually, unzip it, look for sketchy things in the archive manually, then run the APK through Hypatia before sideloading it, because I treat anything served up by APKPure or Aptoide as malware.