Hi mate - so a couple of things:
I’m a volunteer - so i’m not on here doing line chat
There are sometimes issues with the sound, particularly if you have a Bluetooth device connected and take a call or are listening to music at the same - a reboot of the device will usually fix it, but this is something that the team has looked into and it is a device setting issue, not a game issue.
Lagging in pve is device related - there is no server activity except at the end of the match when you get your rewards - if the lag is when getting rewards etc, then it is likely local traffic or server activity.
As for your icon chronicles loss recording as a win - I’m not sure what you mean - did you get the rewards 🤷♀️. Some screen shots would be helpful