When I have a problem with Safari, I just do this, because I do it anyway every few days:
Before, I would recommend just to restart Safari and then reboot your Mac and maybe try if it's happening too with the Technology Preview, if the version isn't outdated like now.
It's not really good if every beta update could brake it. But you can try it anyway. It might crash because it's not intended to use in a beta with a newer version. Mine seems to work. It's already 18.4.
But sometimes just an older build number could break it too.
developer.apple.com
Before, I would recommend just to restart Safari and then reboot your Mac and maybe try if it's happening too with the Technology Preview, if the version isn't outdated like now.
It's not really good if every beta update could brake it. But you can try it anyway. It might crash because it's not intended to use in a beta with a newer version. Mine seems to work. It's already 18.4.
But sometimes just an older build number could break it too.

Resources - Safari - Apple Developer
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