Try df -k /var/run/ and ls -lid /var/run
On my system /var/run/ is a symlink to /run which is a tmpfs. So it's contents will be re-created at every reboot, which will make the -i flag vanish (tmpfs is a filesystem that only exists in ram).

That would explain why chattr -i didn't seem to work. Checking with lsattr might be interesting too.

I doubt wayland would do any better. It looks as if the game has a memory leak, which will probably still happen under wayland.

The only quick fix I can think of is to only run the game for a limited time, then quit it and restart wine before running it again. If it's the sort of game where you can do that.

Yes, I normally disable javascript, for safety. I've managed  to get it now.

Running sort <ps.out1 -g -k 8 | tail against each file in turn to find the programs with biggest RSS I spotted two large users:

R userus+  3114     1 99  80   0 2193540 2241107 -  08:48 ?        00:28:46 C:\Program Files (x86)\StarCraft II\Versions\Base92440\SC2_x64.exe
R userus+  2936  2935 62  80   0 2250356 901302 -   08:48 tty1     00:14:23 /usr/lib/xorg/Xorg -nolisten tcp :0 vt1 -keeptty -auth /tmp/serverauth.LPffKQyAqd

(those are in ps4)
/usr/lib/xorg/Xorg is probably innocent.
C:\Program Files (x86)\StarCraft II\Versions\Base92440\SC2_x64.exe is the most likely culprit.

HTH.

Check what happens if you put a program called poweroff in your path that does something else. Eg the following:

#!/bin/bash
echo In fake poweroff script
id

If that says it's running as root you have a security hole. A malicious person could add something like rm -rF / to it.

Try chattr -i on the file the symlink points to. That might work.

Or (as root):
ls -l /etc/resolv.conf
# Note where it points to (I'll use dest below).
rm /etc/resolv.conf
mv dest /etc/resolv.conf
That should turn /etc/resolv.conf back into a normal file.

The first step is to read the man (or info) pages for free and vmstat. They describe what the output fields mean.

Memory leaks can be a pain to track down. To find out which program is leaking memory you may need to:
ps -efly >ps.out1
Run suspect program (in your case the game under wine) for a while.
ps -efly >ps.out2
Run the program for a bit more.
ps -efly >ps.out3
...
When the system starts paging take a last snapshot:
ps -efly >ps.outn
Then stop the program and compare memory snapshots to see which program(s) RSS and SIZE fields were growing.

Then *all* you have to do is to find who supports the leaky program and persuade them to fix it.

Caveat. I've not had to do that myself, so I can't be sure it will work.

Which ISP is it? That at least tells other people in your country which ISP to avoid.

If you look through the admin screens on the router your ISP provided you might find one saying what IP address it queries (the router will at most cache DNS entries). Assuming it's at 1.2.3.4 (replace that with whatever it is) run the following:
host deb.devuan.org 192.168.1.1
host deb.devuan.org 1.2.3.4
host deb.devuan.org 1.1.1.1

If only the first fails your router is confused. Try power cycling it.
If the first two fail your ISP's DNS server is confused.
If the last one fails something very strange is going on.

The first things I'd try would be ping -c 1 deb.devuan.org and ping -c 1 deb.rr.devuan.org
If the first fails and the second works the I'd try host -v deb.devuan.org which gives more details of how the DNS query works. But I'd be reaching the limit of my knowledge of DNS trying to work out why the one fails and the other works.

Other questions are which country are you in and which ISP do you use (I'm assuming you are doing this from home)? It might be ISP specific.

ifupdown is the name of the suite. It's 3 programs, ifup, ifdown and ifquery (through they are actually the same program called by different names). See their man pages for details.

As a note, it's better to use whereis to check if something is installed. It will find it even if it's not in your path (eg: it might be in /sbin) or only has a man page.

The first thing to check is if your internet connection has had a temporary glitch. Try the apt command again once it's back.

If it's persistent try The-Amnesiac-Philosophers suggestion. Start with host deb.devuan.org, then traceroute against each IP address and use the one with fewest hops (it should be nearest to you) or shortest round trip time.

Next time try which fgrep or whereis fgrep to find where they are on your system.

In case someone else gets something like this:
First try host deb.devuan.org
If it works try ping deb.devuan.org
If that also works try apt update again. It might have been a temporary glitch.
If something fails refer to my last post.

I've spent so much time chasing problems as a system adminstrator it's hard to remember what it's like for a newbie.