Get a Chrome extension running on Safari | Won’t work for all

Extract the crx: https://crxextractor.com/

Or Get the Chrome extension on your Chrome browser & note down the ID of that from the extension menu.

Get the path of the Chrome extension folder:

/Users/<username>/Library/Application Support/Google/Chrome/Default/Extensions/<ID>/<version>

Copy the extension folder to a convenient location on your drive.

Get Xcode installed from the Appstore

Run the following commands

xcrun /Applications/Xcode.app/Contents/Developer/usr/bin/safari-web-extension-converter <chrome_extension_folder>

XCode will open. Press the Run button on it.

Xcode -> Product -> Archive -> Custom -> Development -> Create a dev account ->

Open the preferences of Safari: Command +, Advanced → Show features for web developers

From the save window: Developer -> Allow unsigned extensions

You will need to allow unsigned extensions every time you open Safari.