The One Plus brand has been evolving and moving away from the flagship killer moniker for a while now. These days if you want a true budget phone with decent specs but less software and hardware polish there are plenty of contenders already along with new releases this year like the Xiaomi Pocophone F2 and Meizu 16s.
You're now in the Google Pixel / Samsung territory.
That is the whole point of the Pro; they no longer want to be a flagship killer brand alone but instead offer an actual flagship phone with the hardware and the obvious increase in price to match. One of the main areas that One Plus kept the price down was the screen and they still have that in the 7 (which you rightly say is little more than a upgraded 6T or a 6TT if you will
) but the Pro is there to compete actual flagship phones with the higher resolution along with its main selling point the 90Hz refresh rate.
and IMO they offer far more.
I don't agree that they offer more though, especially when you look at the last two Pixel phones. The Pixel's have always been great phones and I've enjoyed owning them but they are always let down by the hardware which no amount of software can sort. Just look at the screen issues on the 2 XL or the slow down effects caused by low Ram or hardware degradation after a year or so. One Plus phones on the other hand have offered substantially better hardware and build quality for less money, with only the Pixel camera software and screen resolution being a cut above.
Samsung is in a whole different league when it comes to hardware, their screens are the best in the business and that won't change anytime soon. On the flip side the software has always been a bit bloated and clunky which has only been partly sorted by their One UI refresh, you still can't beat OxygenOS. It isn't perfect but it is better than stock Android and anything else on the market. You also have a price tag that puts it above £700-800 One Plus 7 Pro. Imho the Galaxy S10e would be the rightful comparison to it from a price to price basis.
My next phone will essentially come down to what Pixel do with hardware. If they can improve to the point where its up there with One Plus 7 Pro, S10e along with the camera software... then they have a purchase.
It is time to stop thinking about One Plus in the way we are used to. They have been making progressive year on year moves to shake off the flagship killer brand and bring a true flagship to the table. Sure that will cost them some long term more budget savvy users but should also gain them market share. Not all of their decisions will please everyone but then there is no such thing as a perfect smartphone. It is a bit of a gamble but it has been many years in the making and I don't see them turning back now.