Safari

There isn't a single reset function for Safari. Safari/Preferences/Advanced - enable the Develop menu, then go there and Empty Caches. Quit/reopen Safari and test. Then try Safari/History/Show History and delete all history items.  Quit/reopen Safari and test. You can also try try Safari/Clear History…. The down side is it clears all cookies. Doing this may cause some sites to no longer recognize your computer as one that has visited the web site. 

Go to Safari Preferences/Extensions and turn all extensions off. Quit/reopen Safari and test. If okay, turn the extensions on one by one until you figure out what extension is causing the problem.

Try setting up another admin user account in System Preferences/Users & Groups to see if the same problem continues. Please post back on whether or not this worked. Also try the Safe Mode. Please post back on whether or not this worked.

Isolating an issue by using another user account 

Safe Mode - About

If it works in the Safe Mode, try running this program when booted normally and then copy and paste the output in a reply. The program was created by Etresoft, a frequent contributor.  Please use copy and paste as screen shots can be hard to read. Click “Share Report” button in the toolbar, select “Copy to Clipboard” and then paste into a reply. This will show what is running on your computer. No personal information is shown. If the log won’t post, try posting it in Pastebin and provide a link in a reply        Pastebin

Etrecheck – System Information

You are welcome. Go back to where you posted in PasteBin and copy the address in the URL bar and post it in a reply. If you can't find the report, run new one and make a second post in PasteBin, the copy the URl.

Did Safari work in another admin user account and/or the Safe Mode?

I don't see any software that normally causes problems. You computer has 4 GB of RAM installed which is on the low side for modern OS versions. That may be a factor in the spinning beachballs you are seeing. You should consider upgrading your RAM to a minimum of 8 GB.

The 2 places I’ve seen recommended most to buy reliable RAM are below. I have purchased RAM several times, a MacBook Pro battery, and 2 hard drives from Other World Computing and have always been very satisfied with the product and service. They have on-line instructions on how to replace the RAM. OWC has also tested RAM above what Apple states is the maximum. I had 6GB installed on an early 2008 iMac supposedly limited to 4 GB and noticed an improvement.

Crucial

Other World Computing  

You are welcome.

Yes on my MacBook on recovering from internet recovery

You are welcome.