You are overloading your machine significantly.
22:19:44.113: Output 'simple_stream': Number of lagged frames due to rendering lag/stalls: 1312 (11.6%)
22:19:44.113: Output 'simple_stream': Number of dropped frames due to insufficient bandwidth/connection stalls: 404 (5.5%)
22:19:44.137: ==== Streaming Stop ================================================
22:19:44.198: Video stopped, number of skipped frames due to encoding lag: 7227/7387 (97.8%)
The rendering lag entry means that whatever app you are running and trying to capture is using your GPU resources, leaving not enough for OBS. This can be alleviated by (if the app was a game) by capping framerate and reducing in-game fidelity options. Since you're just capturing a window, I don't actually know what you're capturing.
The "encoding lag" entry is even more serious, it indicates that with the veryfast preset you're dropping nearly all your frames, even at a relatively low resolution. Not sure what is using all your CPU cycles, but if you want to have a chance of getting a decent stream with the setup you're running right now, I'd say drop to Ultrafast and then move the other way if things are OK.
I don't know if you've got some runaway process(es) that are eating resources that they shouldn't be, but if you suspect that is the case, I'd suggest making a new ordinary user account on your machine and using that to create a new, blank profile and scene collection in OBS, and run the Auto-Configuration Wizard from the Tools menu, see what settings it suggests, and then try to run a basic setup similar to what you're trying to do and see if you get the same performance problems. If you do that and everything seems fine-- no lag, no dropped frames, then it's possible that either something in your OBS settings (scene collections, etc) has become corrupted and is causing a problem, or something else in your user account is making the machine run more slowly than it should.
If a new user account and a blank profile/scene collection and a run of the wizard results in the same performance problem, then it looks to me like what you're doing is just out of the range of your hardware.
I do know there are issues with OBS on Mojave and I am not sure I expect them all to be addressed satisfactorily as Apple is in the process of deprecating OpenGL (which OBS depends on under MacOS) in favor of Metal. Some capture methods that work on High Sierra and below either don't function or are non-performant. I myself am currently opting not to upgrade to Mojave on any machine that I depend upon to work with OBS.
