Oxc0000001 error after house power failure

Following a blackout, my XPS 8940 (running Windows 11) will not boot. It flashes the Dell logo for perhaps a quarter of a second and then goes into "Preparing automatic repair." When I set the PC to not automatically go there, the screen reports a Oxc0000001 error.

What I've already tried:

SupportAssist OS Recovery:

-- Scan hardware: no issues

Startup Repair:
-- Partition table: ok
-- Boot files: ok

-- Windows health:

"Startup repair was unsuccessful, let's try a system repair:" -- I selected a repair point from November '25. Rebooted. The problem remains.

Next, I tried all the recovery options that the machine boots into (except for the reinstall Windows/factory reset options that result in lost installed programs and personal files). "Quick machine recovery," "System restore," and so on.

For Command prompt (which let me browse directories on X such as /Windows, /Windows/System32, etc., so they're still there), I tried:

bootrec.exe /rebuildbcd - ran successfully

bootrec.exe /fixmbr - ran successfully

bootrec.exe /fixboot -access denied

At this point, I don't know what the other steps to take. I don't know if the problem is in the boot partition, Windows, the SSD that Windows is on, or something else.

In case it was a corrupted BIOS, I did a flash install of the latest BIOS via a thumb drive. It successfully installs, but the booting problem persists.

Can someone please help?