I hear you on switching between Windows/Ubuntu vs. Mac. Especially with Cinnamon which I used at an Alphabet company, the shortcuts were pretty much the same as Windows.
On the Mac, the preference for the Command key is stated explicitly in the human interface guidelines:
• Prefer the Command key as the main modifier key in a keyboard shortcut.
• Prefer the Shift key as a secondary modifier when a shortcut complements another shortcut.
• Use the Option key as a modifier sparingly.
• As much as possible, avoid using the Control key as a modifier.
https://developer.apple.com/design/human-interface-guideline...
We may like or dislike this, but Apple's preference is pretty clear.