I'm running macOS 10.13.6, my Facebook account is included in Internet Accounts under System Preferences and I do not run any of the utilities you mentioned. Not sure what you mean by "view" on my iPhone but I am able to see more postings and can annotate my photos if I use my phone. I also get full access to FB activities if I use Firefox as my browser instead of Safari.
Now, this problem with Safari JUST happened a couple days before I posted the query. Before that it worked fine. I could upload 20 photos and then go back to them to provide a description, tag the photos and provide location info. But not now in Safari. Something similar happened a couple of months ago with my access to the Weather Channel (
weather.com). Previously this website would let me select a number of cities and quickly provide hourly or 10-day forecasts, etc. But the site became unresponsive when using Safari. Could bring up the page but none of the links would respond. However, when I went to the same page using Firefox, everything worked just fine. So something in Safari is not functioning properly. I believe I have cleared the cache using the Develop menu item but I don't know how to prove that since all I do is click on the "Empty Caches" selection.
Finally, I have no idea what Safari Extensions may or may not do for you. I have not intentionally installed any from the App Store.