I also own POCO F3，before purchase the modem，I use phone to test。Both the result about the same.btw，my 5G signal not strong，3 bar only，I think this is why it cannot go beyond 600mbps.

More updates on this 5G CPE I bought from Taobao directly:
1. Form the IMEI check, the modem modules is QUECTEL RM520N-GL. GL means global version, cover mostly all the 5G/4G bands. From another forum somebody slot this module into Mikrotik router and it works fine with Router OS.
3. The SOC part of this modem is from MediaTek
4. The brand is WEYCH or in Chinese 小曼联网 （From box packaging）