Had a good Win upgrade experience from Win10 Pro to Win11 Pro with "legacy HW" that I wanted to share with you.
As you might know, normally you can't install Win11 on older CPUs and without things like TPM etc ...

But with a useful tool Rufus you can not only create installation media on USB stick, but also remove some stuff from the installation media that hinders proper installation. Be warned, it is no standard installation, but on the other hand works fine.

The major steps: *** Backup 1st, e.g. Disk Image using Macrium Reflect Home ***

Used Rufus 4.2 to prepare the official Win11 installation media on USB-3 stick with the goal to make an upgrade installation from the running Win10 Pro to Win11 Pro 22H2 on my legacy hardware.

Rufus modifies the installation media to be able to install without:
  TPM, UEFI, Secure Boot, performance sucking kern virtualisation, online accounts
and to keep the local accounts and also the local Administrator account, if you prefer.

The upgrade installation

Needs to be performed from the running system, best from an Administrator account, if you enabled the local Administrator like I do and by executing setup.exe.

It is advised to disconnect the PC from the network during the upgrade, so that no internet access is possible. This way you keep your local accounts, otherwise you might end up with online accounts.

The upgrade installation went smooth, but is time consuming and needs several reboots.

After installation:

1. I only had to reinstall the MADIface ASIO driver, because MusicBee was unable to find the RME ASIO driver.

2. There was already an icon prepared on desktop to reactivate my beloved 8GadgetPack and my selection of Gadgets.

3. To get the old used Startmenu I had to upgrade from StartIsBack++ to StartAllBack 3.x which is Win11 compatible.
StartAllBack tool finally the old license from StartIsBack++ so that I didn't have to pay additional $2 for it.

First conclusions

The installation looks promising, sound, audio playback, Cubase .. all works fine.

A cool feature in Microsoft Edge allows you to stream YouTube Videos on your TV. This way I can easily stream YouTube on my 4K OLED TV and using the HiFi.
This is finally, my motivation to try Win11 and to keep it as my main OS because I think that I will use this YouTube streaming on TV more often.

My last Win10 Gold image I will deploy for Performance or other comparisons on a 2nd SSD and implement DUAL boot.

The very nice thing, my BIG installation is now 100% complete on both Operating Systems, Win10 and Win11.

So whatever happens, I can switch between both versions as I want (I would only have to save/restore Firefox bookmarks).
Maybe also application defaults folder ... but usually the bookmarks of my main Browser are enough.

Now the usual rest work:
- O&O Win10/11 Shut up review
- disabling of a few things like Teams and the Widgets
- using "Datenträgerbereinigung" to get rid of old Win10 installation

Thanks to RME, all looks very stable and promising on Win11.