Weird Arch issues

So all was basically hunky-dory on this old ASUS laptop (apart from the login
issue; I have to go to a virtual console, login there, and run startx).

Looking at the rat's nest of cables in the "office", I powered everything
down... the router, the interface to AT&T fiber, the MIDI devices, the
laptop....

After the cleanup (much nicer), I powered up and logged in. Then came a couple
of weird issues, and I am not sure why.

1. YouTube took forever to open a video, and would not play. I reinstalled,
   renamed the Chromium and Firefox configuration directories, and eventually
   got them to play. But no sound from YouTube (which would play audio out the
   laptop speakers.  MPD played fine (through the Behringer USB audio box).
   Using yt-dlp to download a video from YouTube worked fine, fast as ever.

   On the Lenovo laptop, no problem. Still at a loss, nothing I've tried
   works. I disabled all Chrome extensions (Dark Reader and Vimium), nada.

2. I wanted to rearrange my music directory and copy it to a USB drive.
   At about 28Gb, it should have taken around 5 minutes to copy.
   Instead, it took hours. Not sure if it's a VM issue. Today I copied
   the music to my Android phone, and it took around 5 minutes.

At times during the copy from the cheapo SSD to the USB, the system
would undergo long pauses.

The output of "sysctl -a | grep dirty":

    vm.dirty_background_bytes = 0
    vm.dirty_background_ratio = 10
    vm.dirty_bytes = 0
    vm.dirty_expire_centisecs = 3000 (5 minutes)
    vm.dirty_ratio = 20
    vm.dirty_writeback_centisecs = 500
    vm.dirtytime_expire_seconds = 43200 (!!)

The setting maintain on the Lenovo.

Sigh.

--
Wear me as a seal upon your heart, as a seal upon your arm; for love is strong
as death, passion cruel as the grave; it blazes up like blazing fire, fiercer
than any flame.  [Song of Solomon 8:6 (NEB)]