Disclaimer: I am running macOS 12.6.9 Monterey. Your mileage may vary.
Disclaimer #2: I do not claim this to be a permanent fix, but it is definitely a nice work-around to a long existing issue with Safari.
Disclaimer #3: This really has saved me from defenestrating my old MacBook Pro.
Note: My edit is at the bottom of the original post. I left the original in tact for posterity. 😎
Today I was messing around with my VO utility settings because I feel there must be something that we end users can do to get away from the infamous "Safari Not Responding" bug of doom. I began by looking over each category and playing around with different ideas, while stress testing Safari by opening several tabs/windows (see: A metric s**t-ton) linking to various sites, including AppleVis, Netflix, YouTube, Blind Mice Mart, AudioVault, Amazon, Audible, Yahoo, and a few random bookmarks I have related to programming.
As you can imagine, I had a "wonderful" time (see: God awful) dealing with Safari freezing up again, and again, and again, and., well you get the idea. 😅
However, I kept at it, until I came up with the following changes to my VO settings. I would swear to you all I have a much, much better time navigating the inter webs with Safari since making these changes, though I will admit they will take a little "getting used to".
The following changes I have listed below. The category and sub category will proceed a bulleted list. I really hope these suggestions work out for you all, as they are for me. Again, I am on Monterey, so Ventura and Sonoma may be a completely different beast.
Note I have only listed my final changes, these are not every setting within the VO utility.
1. Go to Verbosity > Text, and make the following changes:
• When text attributes change: Do Nothing
• When encountering a misspelled word: Do Nothing
• When encountering a link/attachment: Play Tone
• Read numbers as: Words
• When reading a capital letter: Speak Cap
• When deleting text: Play Tone
• Append phonetic pronunciation to single characters: unchecked
2. Go to Web > General, and change the following:
• Disable EVERYTHING!
3. Go to Sound, and change the following:
• Mute Sound Effects: Checked
• Enable audio ducking: unchecked
• Enable positional audio: unchecked
4. Reboot your Mac.
Once you are rebooted and back on your Desktop, open Safari and visit some web pages! If your machine works anything like mine, you will have shortened the "Not Responding" bug from whatever it was before (for you) to practically non-existent. 😎
After further stress-testing my machine, I have come to the conclusion that you really only "need" steps 2 & 3. That makes this a much simpler process, and I swear this really works. Again I do not swear it completely removes the "Safari Not Responding" bug, but it makes it such an insignificant issue that you will likely not be bothered by it.