Vivo x100 Pro

And with regards to Vivo using MTK processors on its phone...did you notice how Vivo collaborates with various brands? ZEISS is the brand that handles Vivo's camera tuning...it's a collab between the two brands. Similarly, Vivo now uses V2 (X90 Pro) and V3 (X100 Pro) chips to get the best camera output; now this is my guess, but I believe these chips are probably more compatible with MTK processors than SD. I could be wrong here, but this is a plausible explanation as to why Vivo uses MTK processors in its flagship series. 

And if this is not the actual reason, then it has to be profit making. What iQOO does is practically insane, providing such great specs (mostly SD phones) at the best prices. I doubt Vivo will do it because Vivo is more about camera performance rather than speed, correct? Also, it's quite clear that Vivo earns the majority of its profits by selling its Vivo branded phones only. Although we know that iQOO is a great brand, most Indians haven't even heard of it or they don't trust this brand enough. So, as of now, iQOO is spending more and earning less; those shortcomings in profits are being managed by Vivo phones that provide average or sometimes below average hardware on their phones. 

It depends totally on the price of the phone

No smartphone processor under Rs. 30K can even be compared with the MediaTek Dimensity 9300 (used in Vivo X100 Pro)

Yes, if you'd compare it with SD 8 Gen 3, I'd prefer SD any day. But, it's not that MTK's processors are bad irrespective of their prices. In fact, I'd say MTK is doing better than SD in the budget segment. SD processors are good AND EXPENSIVE even for brands. You'd hardly see some SD 4 Gen1/2 phones under 20K because those processors are expensive, so brands have to compromise on one thing or another. If you want an SD phone and don't want to compromise on display and other aspects, you'd get the SD 695, the same old processor that I don't love personally. On the other hand, MTK is providing many affordable processors for that price (a bit too many, it's confusing, but brands have a few options at least). 

And if we move to a price range of up to 30K, you would see that there is just one phone with the SD 7 Plus Gen 2 (a beast of a processor), the POCO F5. Why is such a great processor used only on a single phone? Because it's a bit too costly for brands compared to MTK's  Dimensity 8020, 8200, and even Dimensity 9000 (not always, but the Nord 3 is sometimes available for under 30K, more often than iQOO Neo 7 with SD 8+ Gen 1). 

By no means I am saying that MTK is better than SD...nope, not even in a million years. But my point is, what's the point in making such good processors when they are not affordable enough for brands to use in their smartphones? So in that regard, MTK does much better than SD. And when we compare processors, we should always do it within a definite price range. Even the Exynos 990 would be a better processor than the Snapdragon 680...but that doesn't mean that Exynos processors are as good as SD, right?

Mediatek is as good as snapdragon, what's the point here. Depends on power of processor added.