At least use 11 Enterprise (24H2) to mostly avoid the nonstop cacophony of ads. I don't want to hear about 365 or OneDrive or OneNote or Copilot every 3 μs.
Before AppVolumes got bought and became VMware App Volumes, there was Softricity (which became Microsoft App-V).. the app was actually a thin client to talk to a terminal server running the app in a container on a server. Office "installs" in 1 second because it's already "installed" on the app server. The next iteration was AppVolumes streams already installed apps like "Linux snaps" on-demand for Windows to do away with the separate terminal server.
She only uses that laptop for MS Office. She did actually use the browser version for a few months, but even that is a significant downgrade compared to native apps.
MS Office and most popular multiplayer games are the 2 biggest hurdles for Linux adoption at the moment.
I tried using Office on the web for a bit, for some reason there's absolutely no way to disable auto-capitalization on the web, luckily I almost never need to use it anyway, and have LibreOffice and Google Workspace instead.
What were the problems she encountered? I'd assume lag or inelegance, but that can be fixed by using a native Linux solution (i.e. Libreoffice), but I assume you've already tried/rejected that for other reasons. What were those in that case?
Lag was certainly a factor, but there were also weird behaviors like visual glitches and UI rendering issues. There were a number of intermittent problems that are hard to list specifically, as it’s been a few months since we tried it.
She is not a power user. Working inside a container running Windows just to display MS Word introduces complexity. separate file systems, etc. Sometimes the abstraction breaks, and you "fall out" of the app and end up staring at a Windows environment. It is very confusing for a layperson. On top of that, the RAM overhead was significant for her older laptop.
She is a kindergarten teacher. The last thing she can use is friction on her laptop.
We didn't try LibreOffice. I'm familiar with it, but the learning curve/transition is just too much friction. They also share a lot of documents with colleagues. I don't know the current state of compatibility between MS Office and LibreOffice, but I recall layouts breaking regularly. She also has a library of templates originally created in MS Office.
I'm not very proficient nor really need office apps in my day to day use but I've heard good things about OnlyOffice should LibreOffice not meet your needs.