Something is causing a high system load when you ran that second report. In fact the SSD's read speed was very slow, but the write speed was higher.....usually the speeds are reversed since writing to an SSD is usually slower although I have seen a few recent EtreCheck reports where the speeds were reversed like yours here.
Your second report does show this one aspect of One Drive as being loaded (not sure why):
[Engagé] com.microsoft.SyncReporter.plist (Microsoft Corporation - installé 2024-04-29)
Exécutable: /Applications/OneDrive.app/Contents/SyncReporter.app/Contents/MacOS/SyncReporter
Since you are experiencing issues with both user accounts it is most likely something system wide or perhaps a hardware issue of some sort, perhaps with an externally connected device. Make sure to disconnect all external devices in case one of them is causing a problem (or perhaps two of them together are not getting along with one another).
Try creating a new macOS user account. Log out of your main user accounts & log into the new user account. Do not log into your AppleID or iCloud and do not restore/migrate from a backup. Just test out how the laptop behaves while using this bare bones new user account. If you still have issues, then it may be some macOS system wide configuration issue....perhaps a corrupt .plist configuration file.
You have sufficient Free storage space on your internal boot drive that you can try creating a new APFS volume (give it a unique name) where you can install macOS into it right beside your main OS. Do not migrate or restore from a backup. Do not log into your AppleID or iCloud. Do not install any third party software. Make sure to test the new OS in its default configuration to see how it behaves. If you have no issues, then you can try migrating the home user folder to test how the laptop behaves, or you could just migrate just the apps from the backup/other system. You want to test things one at a time to try to see what may trigger the issue with the new clean OS installation. Just make sure to keep at least 20GB+ of Free storage space at all times for the normal operation of macOS. When you decide to delete the new APFS volume & new OS, just make sure to change the default Startup Disk System Settings to point to the OS you are going to keep, otherwise things may get a bit weird after deleting the APFS volume group. This option allows you to dual boot so that you can still use the laptop normally, but after your work is done, you can boot to the new OS for testing.
You can also try a DFU firmware Revive which resets the security enclave chip and system firmware. I doubt this will make any difference though.
You can also try running the Apple Diagnostics to see if any hardware issues are detected.
You can try running Disk Utility First Aid on the hidden Container. Within Disk Utility you may need to click "View" and select "Show All Devices" before the hidden Container appears on the left pane of Disk Utility. Even if First Aid says everything is "Ok", click "Show Details" and scroll through the report to see if any unfixed errors are listed. If there are errors, then run First Aid again until they are gone. To repair some errors, you may need to run First Aid while booted into Recovery Mode (again may need to be run several times). If the errors still remain, then erasing the disk & reinstalling macOS & restoring from a backup will be necessary.
Do you have any backups? I hope you have good backups since there are so many new ways to permanently lose access to the data stored on the internal SSD due to all the new hardware, software, and security changes.
I agree with the others that if the laptop can be connected to the power adapter, then you should use it that way. macOS now defaults to using Optimized Charging so it will exercise the battery to keep it healthy. Of course if you are not near an electrical outlet, then of course use the laptop on the battery. Keep in mind you may never get 10+ hours of battery run time. I find my Apple M-series Macs will sometimes get a lot of battery runtime, but another day it may be greatly diminished even though the laptop is running the exact same apps & performing the same tasks. Screen brightness definitely makes a huge difference in battery run time.