I've had a couple of OnePlus phones, and they were excellent phones and very good value. However, to achieve that good value, you need to cut some corners, and it seems like the corner they cut is the camera. It's not bad, but it's not particularly good either. I don't have the latest iteration, but having read the reviews, it seems that the camera continues to be the weak point.
Regarding Huawei, I really like the P30 Pro, and I actually bought one, but had to send it back immediately after Trump banned Huawei from doing business with American companies (i.e. Google, who pretty much control Android services). The ban was actually imposed while I was still waiting for my phone to arrive, which was that much more of a bummer. So, really good phones in my opinion (and the P30 Pro still has the best camera on any phone currently on the market), but there is uncertainty over the Huawei ban, which could mean that you'll end up with a very expensive phone unable to be updated.