Sonos Arc Harsh and Metallic sound

I’ve read several pages of similar complaints in this topic: https://en.community.sonos.com/topic/show?tid=6843110&fid=228993

I have exact same issue, and I haven’t found any resolution (some people report that the issue was fixed, but I can tell that it’s still the case).

So far what I discovered:

• When I don’t do any TruePlay tuning at all after factory reset, the issue is here
• When I do TruePlay tuning with my iPhone 12 while following the app instructions, it doesn’t help
• When I do TruePay tuning with my girlfriend’s iPhone 12 Mini while following the app instructions, it doesn’t help
• When I do TruePay tuning with my girlfriend’s iPhone 12 Mini while while standing at the first tuning step instead of sitting, it helps greatly, but sound quality still leaves much more to be desired
• When I additionally raise iPhone higher on the second step of tuning, it makes sound more metallic and unpleasant again

What I also discovered while reading the huge topic referenced above is that presumably the issue occurs more frequently in fairly tight apartments (rather than large living room of a private house), and this is my case. Additionally, I have slightly higher ceiling (at about 3.2 meters) than in most of the buildings this size, that’s why I suppose standing instead of sitting changed the result.

Is there any way I get support with my case or my room just isn’t made for Arc? :)