Malware and Safari Redirect

First off, hold the shift key when you launch Safari.

If it already is running use command-option-escape to force quit it.

Then tell Safari not to reload pages.

Then open the Safari menu -> Preferences and remove all extensions.

You can remove Flash from:

https://helpx.adobe.com/flash-player/kb/uninstall-flash-player-mac-os.html

If you still can't get Safari to load the homepage in the preferences, you may have reset Safari using the guide here:

https://support.apple.com/guide/safari/clear-your-browsing-history-sfri47acf5d6/mac

Hey, don't be too hard on yourself. This can happen to anyone ... myself included. Scrupulous agents are "hard as work" to try to make our lives a bit more difficult. It's best to be vigilant, but don't lose any sleep over these kind of things.

I suggest that you try either, or both, Malwarebytes for Mac and/or EtreCheck, to locate and eradicate any potential malware/adware on your Mac.

Malwarebytes offers a free trial so you can see for yourself. However, I would suggest that you try a brody's excellent suggestions first.

Excellent! I'm glad you got it worked out.