I had a similar issue on a MacBook Air and used the instructions on AsK Ubuntu
sudo apt update
sudo apt install firmware-b43-installer
sudo apt install linux-firmware
The kernal drivers should now show in App Center.
The "point of failure" is likely the hardware itself, as the MacBook Pro you're using shipped in autumn 2006. Comparing the specifications of a fully loaded, top-of-the-line MacBook Pro for that year to the recommended hardware for Elementary OS we see this:
MacBook Pro (2,2)
Intel Core2Duo T7600 @ 2.33GHz
Recent Intel i3 ...
There are few things to know here. The default Windows EFI partition of 100MB is too small for Windows and Elementary - Elementary will not be able to install on it. You need to create a second EFI partition of 512MB, format it as FAT32 and with "boot,esp" flags, and then configure your BIOS to boot from the second EFI.
This means you need to ...
Looks like this is a regression due to a major re-write of the sidebar code. There is an issue report already here: https://github.com/elementary/files/issues/1781
There is a PR awaiting review and approval here: https://github.com/elementary/files/pull/1752 which seems to fix this issue although that was its main aim.