If you have good wifi connection it is alright to download firmware however using mobile data only creates issues because of erratic bandwidth Those who say wifi is not good is only a rumour and a myth. If that was the case then Samsung would only provide smartswitch for downloading and remove OTA. I have been using updates only over wifi and never had a single issue in last few years. So if you feel satisfied to use Smartswitch its upto you.
use smart switch and pc or better flash it via odin or through authorised samsung service center as samsung use odin software only for official purposes...wifi and mobile data is not process where samsung provides non A/b partition type Ota software
solve hoga kaise ? pahele wrong procedure se mar gaya display aur thode hi hoga ? I am using note3 ,s9 and note9 I never use mobile data or wifi for software update as I know very well that what samsung software can do if we simply update 🥱