Override the command+tab shortcut in macOS Catalina when using Chrome
According to Apple: "[...] you cannot define keyboard shortcuts for general purpose tasks such as opening an app or switching between apps."
https://support.apple.com/guide/mac-help/use-global-keyboard-shortcuts-mchlp2262/mac
However you can use custom Chrome shortcuts using an extension: https://apple.stackexchange.com/a/341531/197509
I wouldn't bother tho. This behaviour is consistent if you think that Finder uses the same keys regarding tabs, and pretty much any app will follow the same pattern. Getting used with a different scheme will annoy you whenever you sit on another computer. It is way more efficient to just teach your brain to adapt.