Never used Anbox here but just a thought: can you install F-Droid? If you can then you could install Aurora Store which can install apps from Play Store. Then If you need to sign in to Play Store to use your paid apps this might not be an ideal approach since I’ve read here and there that if you use your Google account to sign in to Aurora Google might lock you out from your account. I have never tried to find out 
Edit- you could also download Aurora’s APK directly from: