safari crashing plus other problems, on MacBook Pro, mid-2015

After you've done what Lexipex suggests, you can run Etrecheck.  It is a diagnostic tool that's very useful to us in finding other problems. Also it will give us further specs on your Mac. After it runs post the log file here. It will contain no personal information. Allowing full drive access will improve the quality of the report.

To post the log file click on share report and use the Page icon in your reply window.

1- There is no information whether Fitbit can run correctly in Mojave, either uninstall it, or remove it from the Users&Groups-LoginItems and don't run it for a while.

Also remove AirportUtility from the user loginItems: it does not have to run continuously.

2- throw out all internet plugins.

3- uninstall iobit, uninstall dexcom (don't know what this is), uninstall fitbit/lifescan, make sure that all kexts are removed

4- I would uninstall tandemport too, you can always see later if it is really needed and reinstall.

then restart.

You did well, but there is still something more to do maybe:

Shutdown Safari,

Start Safari while holding the Shift key,

then in Safari->Preferences->Advanced: check the line "Show develop menu....",

then in Safari->Develop: "Empty Caches",

(then clear all history, you already did that),

After that it should be better.

There definitly is something more that is wrong.

The etrecheck list will give more information, as macjack proposed!!

Which model do you have the 13" or the 15"?

Do you have the optional DVD drive in it (15" model)? If yes, is there a DVD in it?

Well, that doesn't sound good.