I have still not updated my m30s to Android 10 because people where complaining so much about new update but after today's july update some people are saying that major issue got resolved in this update.
So should I update now or wait till August update?
Yes. The internal system from server side of FOTA servers will flag his IMEI saying he's not interested in updates. If that happens, he'll never receive updates automatically. You can still force it via ODIN though.