I don't know why every reviewer seems to get so hung up on the lack of IP certification for OnePlus phones.
The US T-Mobile version carries the certification. Does anyone think those phones come off a special assembly line? No, they are exactly the same phones as the non IP rated ones. T-Mobile and OnePlus have probably come to an agreement to share the extra cost of having the certification sticker placed on the box
IP certification has always been excluded on OnePlus devices because for a device to receive it, a certification/license fee has to be paid for every device sold. Since OnePlus is trying to offer flagship features at a mid range phone price, some value engineering decisions have to be made. You can't have everything and still pay less.
For the price, you get a high performance phone, with a really nice screen, that will last 4-5 years without performance degradation (I am still running a 4 year old OnePlus 6 that is only on the way out because the USB port is starting to play up). The camera may not be as good as an iPhone or top end Samsung, but you pay a lot more for those! And unless you professionally create content on your phone, you probably wouldn't notice the difference anyway. Most of us aren't doing this, we take photos to post on Insta, or share on a messaging app.
Not only that, all credibility in this article is shot by the reviewer getting the manufacturer/parent company completely wrong. OnePlus is part of Oppo, not Huawei!