As mentioned by @deHakkelaar I have had a look at monit and got it working quite quickly just based on their manual and examples:
It's a web server running on a different port on the same machine as pi-hole, displaying current system stats, ssh details and - and I did this just for testing purposes without any need - the first ten entries returned by top. This has been set up in less than 30 minutes.
Maybe this is a solution for all those using for the stats being gone?
All the best
Changing an interface to a new style and having no option to get back to the old (better: well known) style was, is and will be not a wise plan. Why? There're many good reasons for that statement. Just picking one: Changing the interface imposes the - many - users changing their habits and force them to forget, what they've learned (some folks call this skills) and start from scratch again. Have you ever thought, how many hours were spent to make yourself comfortable w/ a software GUI? And if you've reached the point, that you finally know where certain commands are located, then somebody changes the whole thing again to something different and you've to start to learn all over again, would you really like to spend applause for that? I guess not. So, make a long story short: Please, give the PiHole user community the option to choose, which version of the GUI they want to use. Many thanx in advance.
We have changed the interface many times over the past 5 years, along with many options available from the web admin GUI.
I can't think of a software package I use regularly that hasn't had an interface change.
With a little DuckDuckGo magic I was even able to monitor the GPU temperature on my Raspi.
And I adjusted settings a bit so I can login from a remote machine:
pi@ph5b:~ $ sudo nano /etc/monit/monitrc
[..]
set mailserver localhost
set alert my@mail.address not on { instance, action }
set httpd port 2812 and
use address 0.0.0.0
allow 0.0.0.0/0.0.0.0
allow admin:monit
We need a script for this:
pi@ph5b:~ $ sudo mkdir /etc/monit/scripts
pi@ph5b:~ $
pi@ph5b:~ $ sudo nano /etc/monit/scripts/cputemp.sh
#!/bin/sh
CPUTEMP=$(vcgencmd measure_temp | sed "s/temp=//; s/\..'C//")
exit $CPUTEMP
pi@ph5b:~ $ sudo chmod +x /etc/monit/scripts/cputemp.sh
pi@ph5b:~ $
pi@ph5b:~ $ /etc/monit/scripts/cputemp.sh; echo $?
49
A nice separate config file for monit:
pi@ph5b:~ $ sudo nano /etc/monit/conf-available/cputemp
check program CPU-temp with path "/etc/monit/scripts/cputemp.sh"
if status > 45 then alert
Symlink in the enabled folder:
pi@ph5b:~ $ sudo ln -s /etc/monit/conf-available/cputemp /etc/monit/conf-enabled/
pi@ph5b:~ $
Activate changes:
pi@ph5b:~ $ sudo monit reload
Reinitializing monit daemon
And soon after:
pi@ph5b:~ $ tail -F /var/log/monit.log
[..]
[2022-09-11T15:48:23+0200] error : 'CPU-temp' status failed (49) -- no output
pi@ph5b:~ $ sudo monit status CPU-temp
Monit 5.27.2 uptime: 30m
Program 'CPU-temp'
status Status failed
monitoring status Monitored
monitoring mode active
on reboot start
last exit value 49
last output -
data collected Sun, 11 Sep 2022 15:48:23
A mail in my inbox:
Subject : monit alert -- Status failed CPU-temp
Sender : monit@ph5b.home.dehakkelaar.nl
Recipient: my@mail.adress
Date : Today 15:48Status failed Service CPU-temp
Date: Sun, 11 Sep 2022 15:44:33
Action: alert
Host: ph5b
Description: status failed (49) -- no outputYour faithful employee,
Monit
And webGUI status:
It keeps mailing me every 4 minutes or so tough 
But I am able to disable monitoring temperatures via the webGUI.
And oc I changed the temperature threshold to a sensible 80'C.
I believe a Raspi starts throttling the CPU/GPU clock at about 90'C ... ish.
It took me little over 30 minutes ... ish 
EDIT: Ow the mailing stopped ... pew.
I agree with your statement that users need to adapt to the new interface and acquire new "skills". However, it's quite uncommon to offer options to go back to old versions for every change in the UI which is made. At least I don't see an option to get back the old Win 3.1 style I loved to much
