I think that you shouldn't just assume that the RX 6650 XT is the best value because of some because of some YouTube comparisons. I can tell you just from looking at your list that it isn't. I'll show you what I mean.
According to TechPowerUp's GPU database... <-click to look at it
The RX 6750 XT is 21% faster than the RX 6650 XT on average.
588 ÷ 440 = 1.336
You'd be paying 33.6% more for 21% more performance.
Therefore, the RX 6650 XT is better value than the RX 6750 XT.
The RX 6800 XT is 63% faster than the RX 6650 XT on average.
709.90 ÷ 440 = 1.613
You'd be paying 61.3% more for 63% more performance.
Therefore, the RX 6800 XT is better value than the RX 6650 XT.
The RX 6950 XT is 87% faster than the RX 6650 XT.
839.90 ÷ 440 = 1.908
You'd be paying 90.8% more for 87% more performance.
Therefore, the RX 6650 XT is better value than the RX 6950 XT.
The TechPowerUp GPU database is generally accepted as the last word when it comes to comparing video cards because TPU looks at several reviews (including their own) and averages them all out to give a more accurate metric.
Ok, so there's no question here that the RX 6800 XT is the best value . It is, on average, 63% faster than the RX 6650 XT but only costs 61% more. It won't limit you in games and will be viable for far longer than the RX 6650 XT, especially considering that it has literally double the VRAM (16GB vs 8GB).
Having said that, this really also depends on what it is you're looking for. You have to take into account the monitor that you're going to use. If it's only a 1080p/60Hz display, then the RX 6650 XT is the way to go because you won't be able to leverage the extra performance offered by the RX 6800 XT. Your experience will therefore be exactly the same with both cards, limited by the capabilities of your monitor.
What makes the RX 6800 XT so desirable here is that it breaks the rule of diminishing returns. Generally, the more that you go up in performance, the more that the value of a card will go down. This is because as you go up, you're not just paying X amount of Euros per frame, you're also paying extra for the card's overall increased capability, longevity and VRAM. You're paying for the ability to be less limited in what settings you can game with. However, in this case, the RX 6800 XT is a
better value than a card that's WAY down the ladder from it.
Overall, I'd say that the RX 6800 XT wins big in this comparison and it is
definitely the card that I'd choose. Oh wait, that's right, I DID choose it! As the owner of an RX 6800 XT, I can say quite truthfully that you'll love it if you buy it.