Boot method: <How did you boot the installer? CD/DVD? USB stick? Network?>
From a working Debian 11, mounted an image of Debian 11, and modified
/etc/apt/sources.list to use this, and other Bullseye repositories.

Image version: Debian 11 iso plus internet
Date: Soon after official Debian 11 officially became stable

Machine: HP Spectre x360 Convertible 15-df0xxx
Processor: Intel(R) Core(TM) i7-8750H CPU
Memory: 16GiB
Partitions: Separate '/home' and '/'

Output of lspci -knn (or lspci -nn):
See end of this message

Base System Installation Checklist:
[O] = OK, [E] = Error (please elaborate below), [ ] = didn't try it

Initial boot:           [E]
Detect network card:    [O]
Configure network:      [O]
Detect media:           [O]
Load installer modules: [ ]
Detect hard drives:     [O]
Partition hard drives:  [ ]
Install base system:    [ ]
Clock/timezone setup:   [?]
User/password setup:    [ ]
Install tasks:          [O]
Install boot loader:    [O]
Overall install:        [E]

Comments/Problems:

<Description of the install, in prose, and any thoughts, comments
      and ideas you had during the initial install.>

Normally from off it only takes like 15 seconds to be completely loaded and
logged in. After install time to start up was way over a minute more, and then
same after logging in. Things seemed to be mostly working ok after that.
I noticed that it wouldn't ping the ntp server.
Internet/Firefox was working.
Hibernate and suspend didn't work (they didn't work under Debian 10 either, I
think they may have worked with kernel 5.4 but not Debian's 10's kernels 4.19
and 5.10)

Decided to revert back to Debian 10 due to this log in delay being way too long,
etc...  (using the partition backup I made right before installing 11)
Tried 1st just putting my backup of '/' partition (without restoring '/home' as
well for now) and there were KDEPIM issues.
Also the pre-grub 'splash' welcome to grub text stayed from the Debian 11
install. There wasn't one before. (is there a way to make it not show this?)