Safari virtually unusable, slow to load webpages if it manages to load at all

Thanks for letting us know, Argonaut386. From here, let's try this in a new user account, as this can help us determine if this is happening in other places on your computer: Add a user or group on Mac

1. On your Mac, choose Apple menu  > System Settings, then click Users & Groups  in the sidebar. (You may need to scroll down.)

2. Click the Add Account button below the list of users on the right (you may be asked to enter your password.)

3. Click the New Account pop-up menu, then choose a type of user.

• Administrator: An administrator can add and manage other users, install apps, and change settings. The new user you create when you first set up your Mac is an administrator. Your Mac can have multiple administrators. You can create new ones, and convert standard users to administrators. Don’t set up automatic login for an administrator. If you do, someone could simply restart your Mac and gain access with administrator privileges. To keep your Mac secure, don’t share administrator names and passwords.

• Standard: Standard users are set up by an administrator. Standard users can install apps and change their own settings, but can’t add other users or change other users’ settings.

• Sharing Only: Sharing-only users can access shared files remotely, but can’t log in to the computer or change settings. To give the user permission to access your shared files or screen, you may need to change options in File Sharing, Screen Sharing, or Remote Management settings. See Set up file sharing and Share the screen of another Mac.

For more information about the options for each type of user, click the Help button in the lower-left corner of the dialog.

4. Enter a full name for the new user. An account name is generated automatically. To use a different account name, enter it now—you can’t change it later.

5. Enter a password for the user, then enter it again to verify. Enter a password hint to help the user remember their password.

6. Click Create User.

7. Depending on the type of user you create, you can also do any of the following:

• For an administrator, select “Allow user to administer this computer.”

• Select “Allow user to reset password using Apple ID.” To use this option, the user must have set up iCloud on this Mac. However, this option isn’t available if is FileVaultis turned on and set to allow the user to reset their password at startup using their Apple ID.

•Use Sharing settings to specify whether the user can share your files and share your screen."

Let us know, and we'll go from there.

Regards.

Hi Argonaut386,

Thank you for using the Apple Support Communities! We see you were linked from the article "If Safari isn't loading websites or quits on your iPhone, iPad, or iPod touch" For this issue, we would suggest the steps in the article below specific to Mac:

If Safari on Mac doesn't open a webpage or isn’t working as expected

Test with a private window 

A website can store cookies, caches, and other data on your Mac, and issues with that data can affect your use of the website. To prevent the website from using that data, view it in a private window. From the menu bar in Safari, choose File > New Private Window, or press Shift-Command-N.

If that works, use the following steps to remove the website's data, including its caches and cookies. The website can then create new data as needed. If it's a website that you sign in to, make sure that you know your sign-in information before continuing.

1. Choose Safari > Settings (or Preferences), then click Privacy.

2. Click Manage Website Data.

3. Select the affected website from the list shown.

4. Click Remove.

5. Click Done.

6. Open the website again in a non-private browser window.

Check VPN or other security software

If you installed VPN or other software that monitors or interacts with your network connections, that software could affect your use of the website or the internet. Learn about network issues related to VPN and other software. 

Check network settings

Certain network settings, such as those related to using a proxy server or custom DNS server, can affect access to content on the internet. Even if you haven't changed your network settings, you might have installed software that changed those settings for you.

To find out whether the issue is with the network settings on your Mac, try viewing the website from some other device connected to the same network.

To find out whether the issue is with your network itself, try viewing the website after connecting to a different network.

Hope this helps!

Have a great day.