More on that... I'm not sure what I did, but I managed to get those extraneous sites "Banned" in that plist, and they haven't reloaded after quitting Safari and even restarting.

At one point I locked the file, but it didn't seem to do any good...maybe needed a restart, but it's no longer locked, and my only Top Site is the one I want to see.

I'll bet you could edit your file to look like mine.

Code:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
	<key>BannedURLStrings</key>
	<array>
		<string>http://www.wikipedia.org</string>
		<string>http://www.facebook.com</string>
		<string>http://www.tripadvisor.com</string>
		<string>http://www.linkedin.com</string>
		<string>http://www.bing.com</string>
		<string>http://www.icloud.com</string>
		<string>http://www.finetunedmac.com/forums/ubbthreads.php</string>
		<string>http://www.yahoo.com</string>
		<string>http://www.google.com</string>
		<string>http://www.yelp.com</string>
		<string>http://www.twitter.com</string>
		<string>http://www.weather.com</string>
		<string>http://www.apple.com/startpage</string>
	</array>
	<key>DemoSites</key>
	<array/>
	<key>DisplayedSitesLastModified</key>
	<date>2019-09-05T17:59:46Z</date>
	<key>TopSites</key>
	<array>
		<dict>
			<key>TopSiteIsPinned</key>
			<true/>
			<key>TopSiteTitle</key>
			<string>WQXR | New York's Classical Music Radio Station</string>
			<key>TopSiteURLString</key>
			<string>https://www.wqxr.org/</string>
		</dict>
		<dict>
			<key>TopSiteIsBuiltIn</key>
			<true/>
			<key>TopSiteURLString</key>
			<string></string>
		</dict>
	</array>
</dict>
</plist>

The new Great Equalizer is the SEND button.

In Memory of Harv: Those who can make you believe absurdities can make you commit atrocities. ~Voltaire