CPU hard and soft lockups - desktop crashing

[tkn]

I am afraid that it is, with a very high probability, a hardware failure.
CPU Hard & Soft lockup errors practically always point to a piece of hardware failing.
(but a loose connector can do the same type of damage)

After doing a full backup of your home directory, redownload and reinstall kernel 5.15.06-56 because it is, again with a high probability, corrupted by whatever-it-is-that-happened.

Checklist:
A. Connections
B. Temperatures
C. Harddisk or SolidStateDrive health
D. RAM
E. Powersupply

A. Connections:

1. clean the inside of your PC case
2. reseat your GPU and your ram-sticks (to ensure good contact)
3. disconnect and reconnect the SATA cables and the powerconnectors.
   make sure the connectors fit 'snugly' i.e. not too loose/flexy.
   replace cables that look dodgy.

B. Temperatures: just check, and keep an eye on it.

C. Possibly your HD/SSD is slowly deteriorating.
A very good and useful "how to check" is written by @ricmarques here:

All Indications Point To Disk Corruption

Hi, @OldStrummer (Fred). You mention that you have "20Tb of disk"?! That's a lot! Is that a single disk (given the huge size, I'm assuming it's an HDD and not an SSD) or is it some kind of RAID setup with several disks? Before running "fsck" (filesystem check), I would first: 1 - Check the /var/log/syslog and search for disk errors there (messages like "DRDY ERR" and/or "Unrecovered read error" and/or "I/O error" are likely indicators of disk problems and/or a bad cable). 2 - Do you have a g…

D. Memorycheck: A failing element on a ram-stick can cause CPU lockups and data corruption.
Most linux live ISOs have a memorycheck option in the bootmenu.
Let it run for 12 hours or so. Physical ram-errors will not always show up after a short single run.

E. check your powersupply.
A failing or overloaded powersupply can starve the motherboard which can lead to instable and erratic behaviour. If it smells bad or is generating a whining sound, it's dying.
(also, check if the powerrating is a step or two above sufficient for the load of your CPU+GPU+Motherboard)

There are, ofcourse, more possible causes.
The checklist above is just a small list of the most probable causes.

P.S.
Also, because you are in the USA, check if any brownouts or other instabilities of the electricity supply/net/grid happened in your district. Brownouts can pretty much mess up your computer.