Bork, you finally got me to order a damn mClassic for this.
Hell yeah mclassic slays
I mean, I still don't believe in post-rendering upscalers/effects injectors. Once the image has been rendered I don't believe you can really improve it without damaging the original image quality.
Like on PC, a lot of people looooove using ReShade, but I've never seen one single time ReShade has improved the visuals of a game. It usually just changes the look/art direction to something different from the original intent.
I think FXAA is a post-processing AA injector solution which is why it's low gpu/cpu cost, and FXAA has always been shit since it just blurs stuff. Only sorta works when done at a higher resolution and downscaled to native resolution imo.
But, PC is different because you can internally render almost all games at high resolution so you don't need post-processing injectors. I will entertain the idea that on stuff like Switch, it's possible that it helps, though I'm not expecting much out of mClassic, but I'll give it a shot.
I didn't buy into the mClassic until thoroughly researching it and seeing countless positive reviews. How much it improves image quality is a per-game thing for sure and from my experience, the best image quality you can get is when using the device hooked up to a 1440P monitor or a TV that accepts a 1440P signal. If you're using it on a 4K TV that doesn't have 1440P support, it's only going to upscale to 1080P,
*but* it will still look better than just using a normal HDMI connection.
Another thing to keep in mind is that the best image quality settings are also per-game, which just means that if the game is running at 1080P docked, you want the Switch video output set to 1080P, but if it's running at a lower resolution docked, it's recommended to change it to 720P for better results. You don't have to do any of this, to note, but it's something to try for optimal quality. I generally just leave my Switch on 720P output and let it upscale all the games to 1080P on my TV and it looks really nice. It's also easy to mess with video output on Switch since you can change the resolution at any time while a game is running through the Switch options menu.
If you don't want to use the mClassic with a game, it has a switch to disable it, btw. You don't have to unhook it from your TV. It also has an additional setting to force a 4:3 aspect ratio which is nice when using it on displays that stretch images to 16:9 on older hardware.
Finally, it may seem obvious, but only use the mClassic with your Switch or older hardware. If you have an HDMI switch hooked up to your TV and your PS5 is connected, you may experience issues with games displaying correctly and HDR won't work with the mClassic. And also just want to note that it needs its own power source to work, but USB works so you can just power it through the Switch dock.
IMO the best-looking game to try and see the difference with is Monster Hunter, followed by Xenoblade.