Enter Unicode Special Characters with Windows Alt Code

We are running on our nextcloud

COOLWSD version: (git hash: 80a6f97 (E))
LOKit version: Collabora Office (git hash: 4fe480d)
Served by: Debian GNU/Linux 12 (bookworm)
Server ID: ed55c1c7

We’d like to enter some special characters like ± in a spreadsheet.
We use this special characters quite often and are used to enter Alt+0157 for this on windows clients. Unfortunately there is the shortcut for format cells on Alt+0 that makes it impossible to enter special characters, where the Alt code starts with 0. Other Alt codes work like a charm.

Is it possible to deactivate this shortcut on a per user basis or global as nextcloud administrator?

I found the help documentation that says that we can assign other shortcuts under Tools - Customize - Keyboard

When I activate compact view, I found the tools menu but there is no customize entry.

On the same page there is a section about unicode characters by entering the hex code and pressing Alt+X. I tried this on my Windows client with Firefox (Shift+Alt+X) and Chrome with U+00B1 or just 00B1 and on a Linux virtual machine with firefox and chromium, but nothing happens.