Pizzasgood

Look in /var/log/Xorg.0.log for Xorg errors.

Check if OpenGL is okay by running glxinfo (from the package mesa-utils) and checking in the first few lines for "direct rendering: Yes".

Check if Vulkan is okay by running vulkaninfo (from the package vulkan-tools) and seeing... if it throws errors at you, I guess. There are probably some specific things you could look for but I'm not familiar enough with Vulkan yet.

You could sudo dmesg and read through looking for problems, but there might be a lot of noise to sift through. I'd start by piping it through grep -i nvidia to look for driver-specific stuff.

Might be worth running nvidia-settings and poking around to see if anything seems amiss. Not sure what you'd actually be looking for, but yeah.

Sometimes switching from linux and nvidia to linux-lts and nvidia-lts can help if the problem is in the kernel or driver. Remember to switch both of these at the same time, since drivers need to match the kernel.

You could also try switching from the nvidia drivers to nouveau. Might offer temporary relief and help narrow down where the problem is, at the expense of probably worse performance in heavy games. Ought to be fine for 2D gaming and general desktopping.

Trying a different window manager is always an option. Don't know how much hassle that is when you use a full DE; I've always been the "just grab individual lightweight pieces and slap 'em together" sort so I don't have any real experience with KDE. But yeah. Find out what the right way to change WM is for your system, then try swapping over to Openbox or something minimal like that and see what happens.

Related to WM/DE, it could be an issue with the compositor maybe. Look up whatever KDE's compositor is and see if you can turn it off and run a different one?

That does rule out the creators, yeah.

When you say it happens instantly, do you mean that you instantly get a "Post deleted" notification of some sort, or just that you hit "Reply" and the post never shows up?

I ask because there's a blog I comment on sometimes that occasionally pretends like it's posting my comment, but then the comment doesn't appear. My first assumption was that I was encountering some kind of moderation filter, but it turns out I wasn't. That blog just has poorly designed error handling. If I take too long to write my comment, the session expires. That's fine and normal, but the problem is that the blog software doesn't bother to warn me before posting, and it doesn't explain itself after the post fails, so it creates confusion. Once I realized what was going on though, I realized I could just hit "Back" to recover and copy the comment I wrote, reload the page to get a fresh session, paste the comment, and hit "Reply." Works totally fine that way.

Maybe YouTube is doing something similar and dropping attempted comments due to expired tokens or shoddy networking? It would explain why it seems so random and nonsensical.

If it really is bad auto-mod systems, there probably isn't much you can do about it besides complain to YouTube. Any workaround that would be easy for you to use would be equally easy for the spammers and trolls to use, and is therefor not likely to remain a usable workaround for long.

As far as I know, none of my (very few) comments have been deleted yet, so I'm curious how that works and how you know who was responsible. Do they notify you when it happens and explain who made the decision?

No. Thinking about the panda is involuntary in that scenario. Typing up and submitting an explicitly unwanted response is not involuntary. It's a thing a person chooses to do expressly against the wishes of the person making the request.

Don't ease into it at all. Wait for a moment where it would be funny, then go whole hog with it. Treat it like a joke... but then just keep going. Never go back. Don't even acknowledge there is a back. Pretend this is how you've always talked and they're insane if they think otherwise.

I don't know if this is the case for other people, but I have to be careful about using slurs in any context because the more I see or use a word the more likely it is to slip out in other situations. I'd never purposefully use a slur on somebody, but my word-choices are largely running on automatic when I'm angry. I just push intent at my mouth and then my subconscious picks out words matching that intent and feeds them into my tongue. If I push the intent "strong targeted insult" into that system, a slur could match those parameters and make it out my mouth before my conscious mind can catch and filter it. Entirely avoiding using slurs, and ideally avoiding even thinking slurs helps to avoid this happening (both by avoiding them entering my vocabulary-supply in the first place, and by building the mental reflex to immediately drop them like they're hot if they do pop into my brain).

A more society-level reason to discourage people from publicly using slurs even in discussions about them is to make it harder for bigots to stage "discussions" as excuses to loudly use slurs while in earshot of the people they'd like to use those slurs at.

People also get paranoid about automated (or braindead) moderation, or trolls who shame people based purely on the fact that a quick and context-free search of their post history turns up N uses of a slur. It's often easier to just dodge these kinds of problems than to fight them.