I've updated the OP with Version 3.0 of Scroll to Top or Bottom of Macro:
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For scrolling to the bottom, simplified the logic using an AppleScript approach by @Nige_S.
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The above change eliminates two earlier requirements: 1) The System Setting (or System Preference) Show scroll bars had to be set to Always, and 2) The entire Keyboard Maestro editor had to be visible on the mac display.