winbar VS cassowary

You don't even need to customize the taskbar. There's winbar

You can give it a try from: https://github.com/jmanc3/winbar

I'm using virtualbox on my x220, of I really need windows. However, if you setup a VM from scratch anyway, I would rather go with KVM/QEMU and maybe even try https://github.com/casualsnek/cassowary, to launch the windows programms directly under Linux, with the VM running "in the background".

Overall, don't be afraid to switch distro (use Ventoy, load a few ISOs just in case), try to make sure you have an easy way of backing up your stuff (be it with a separate /home partition, or like I do with storing everything important in a separate drive and then using symlink to make it 'appear' in their 'default' places), and you can always use VM in a pinch (consult this guide or use quickemu or gnome-boxes)

In case some things you do absolutely needs Windows, keep this guide for setting up VM in mind, or use quickemu's GUI.

How are integrated VM solutions like cassowary on the surface pro? I need to run OneNote (this is a must as I am set all work on OneNote) to a decent level, with pen support.

Well, if I actually need office 365 for collaborating with someone, I use https://github.com/casualsnek/cassowary to actually run the Office Suite in a Windows VM and have it seeminglessly integrated into Linux.

Microsoft Office run in a Windows VM and integrated into Linux via Cassowary (https://github.com/casualsnek/cassowary). This requires installing libvirt and virt-manager in a rootful Distrobox (apparently Distrobox supports this only for Alma Linux and Tumbleweed, so the default Tumbleweed guest should be okay as long as you can run it with root) and installing the Python application Cassowary ("pip install cassowary") that then "finds" Microsoft Office in the VM and integrates it via FreeRDP so that you can for example click on an XLSX file in Dolphin and it opens in MS Excel running in the VM. Can this approach still work all in a Distrobox? So that basically I click on an XLSX file and it then opens in MS Excel running in the Windows VM in the Distrobox via Cassowary in the Distrobox? There's a lot of layers here, namely: MicroOS -> Distrobox -> [Cassowary + FreeRDP + Virt-Manager + libvirt] -> Windows VM -> MS Office, and I wonder if this would even work.

Imo QEMU/KVM has better performance than VirtualBox. There are also some tools like Cassowary to make Windows apps run as if they're native apps (e.g. without opening VM first). It's harder to setup than VirtualBox, though.

If you need to use complex Windows-only programs, use the KVM with GPU passthrough and cassowary. If it's reported to be working fine by the Wine's AppDB, you may want to use wine flatpak.