FWIW, Feather Wallet also could have slow sync since it download check all block from specific block height (either when the wallet created or first time you receive Monero) due to privacy purpose[1].
I've had that with "Bitcoin Wallet" on Android, restoring my old backup took more than a day on my old phone. It's okay, I haven't been able to use it from Coinomi in about a year, so I'm in no rush.