Poking around System Settings > Keyboard > Keyboard Shortcuts… > Keyboard is a pretty good place to browse if you haven't. There are default keybindings that can changed and switched on/off. For macOS Sequoia 15.6:

    [ ]  Change the way Tab moves focus            ⌃F7
    [ ]  Turn keyboard access on or off            ⌃F1
    [ ]  Move focus on the menu bar                ⌃F2
    [ ]  Move focus on the Dock                    ⌃F3
    [ ]  Move focus to the active or next window   ⌃F4
    [ ]  Move focus to the window toolbar          ⌃F5
    [ ]  Move focus to the floating window         ⌃F6
    [*]  Move focus to next window                  ⌘`
    [ ]  Move focus to status menus                ⌃F8
    [ ]  Show contextual menu                      ⌃↩

I only have one checked currently; I'm not feeling adventurous.