I got a maxed out Tab S8 ultra on launch and this morning I got a 12.9 M1 pro.
In my opinion iPadOS is far from trash, I actually like it, but it's limited, OneUI is definitely a superior OS in almost everything.
That does not make the S8 ultra a better device than the M1 pro.
Hardware-wise the iPad pro is superior in everything except size (which is the main reason why I bought the S8 ultra)
The screen is better (because it's less reflective), the speed is amazing, not even close when browsing, there is hardly any accidental touch (which is for me the main issue with the Samsung tablets that have small bezels) and the magic keyboard is also superior.
And there are better apps in the store, although for my I use (I don't draw) they are almost on par on that front.
So it's basically better hardware vs better OS (and a few more pro apps, but that really depends on the apps you use)
I really wish the iPad pro had some of the features of OneUI and that the S8 ultra had the hardware of the iPad pro (but keep its size). It would be much easier for Apple to make iPadOS better than for Samsung to catch up with the hardware.
Having said that both can be very limiting for work if you need desktop software for your work.
The main reason for me getting iPad was the vast amount of capable iPadOS apps that were well reviewed and that neither have Android versions nor Android alternatives.
If not for that, I wouldnt probably own an iPad now, its all about apps, no limitations if compared to Android which has pretty paltry choice compared to iOS/iPadOS.
Looking from todays perspective and my own experience:
Samsung tablets, higher tier ones, come with OLED displays, which I would prefer over miniLED in my 12.9.
Also, Samsung have upped their game when it comes to number of major OS upgrades and security upgrades, its now longer than it was and pretty considerable imho.
Where I live, Samsung has lots of promotions with freebies and cashbacks for their devices, Apple has basically none, while Samsungs are rather generous ones!
iPads, on the other hand, have more powerful innards which makes them, at least theoretically, much more capable in handling demanding tasks.
iPadOS also has considerably longer and, imho, better software support and update cycle.
And, yes, apps still remain the main factor even today, after 3 years with iPads, for me.
But, yes, iPadOS has lots to learn from DeX, and Im not sure if Apple will ever bring proper external display, multitasking support, let alone MAC apps to iPads.
If they do, I wouldnt find any issues investing-upgrading to 1TB/2TB model of 12.9 when the new one comes out and using it as my computer replacement instead of thinking about M1 series Macbooks or updated Surface's in the near future(summer/autumn).