My Sub 4 seems to be performing as it should. Have you tried unplugging the Arc Ultra and Sub 4 from power for about a minute?

Yes I did a reboot on both subs the arc and both fives as well

Did you check your Sub Audio and EQ settings? Did you make sure Night Sound is disabled?

Yes did all of that

Are any of your speakers wired with an ethernet cable?

The Arc is

Make sure you keep WiFi enabled on all speakers in the Sonos app including the Arc.

Ok everything's been connected by Wi-Fi I just tried to ethernet cord today as a possible solution to what was going on but will do

You can keep the Arc connected via ethernet. Just make sure the Connection setting for the Arc Ultra in the Sonos app is set to “Enable WiFi”.

Gotcha thanks