Thanks for taking the time to do this benchmark.
Unfortunately, I was not able to reproduce your results. I used Zingo Mobile 1.3.0 for Android and restored an 11-month-old wallet (birth height = 1997893). That took more than 8 hours. (My screen recording stopped after 5h:30 but there was 40% left to do).
I did the same test with YWallet and it finished in 15 minutes.
Maybe the good results you got are due to much better hardware than what I am using (since you are sharding).
My phone specs are average. It is a OnePlust 5T and is worth less than 200 USD on ebay now.
Do you have suggestions on how to make Zingo run faster?