RhiRhiCS melagigante This is the same dxdiag from the same system. Are these both your accounts, or are you two different people sharing the same computer? Either way, it would be easiest to have this conversation with one person/account at a time.
For the issue itself, are you running Sims 4 at a 3840x2160 resolution, to match your monitor; or a lower one? If you're playing at 4k, please try 1920x1080 instead just to see whether it helps. Your GTX 970 is still a capable GPU but might be having trouble keeping up with the demands of rendering so many pixels at once.
If that doesn't help, please try playing with your computer offline, just as a test. You can sign into the EA App and put it in offline mode, then disable wifi and/or disconnect the ethernet cable before pressing Play. I realize this is not a workable solution, but it is a useful data point.