Hey,
If you are looking to upgrade your current laptop, I honestly would only recommend that 2019 macbook pro you mentioned. It’s the only machine in this list which will sufficiently up your CPU, RAM and GPU compared to what you have right now. You get better CPU, twice the memory and a better GPU. So it has the best chances at improving your experience.
I would strongly avoid the 2013 MacPro, since it is not only old, but also just plain worse than even your current setup. Premiere doesnt like Xeon CPU’s that much and the i7/i9 is highly likely to outperform it in any situation. Those machines are also notorious for overheating.
I would not yet recommend any of the M1 macs at the moment, since Adobe does not have a native ARM version of Premiere Pro yet. It is in beta, with a reduced set of features right now. I’m also not sure it would really outperform your current setup, since most benchmarks we know focus heavily on comparing it to the machines the M1 replace (and the numbers are very promising in those situations). But outperforming the original Mac Mini or 13 inch macbooks is not that difficult a feat to accomplish. The M1 is an insanely promising future to look out for, but I would wait for the higher end machines like a 16 inch of 27 inch iMac. Adobe will have caught up by then too and all will be well.
One extra route to look for is to augment your setup with external hardware to help you offload the task of the screen sharing to the external device. A combination of a dedicated hardware encoder like BMD’s web presenter (which converts Premiere Pro’s video output to a sort of webcam stream) and Loopback Audio (which allows you to route PPRO’s audio to a zoom call) might also reduce the strain on your CPU needing to encode the video for screen sharing, keeping more power for the NLE software. Found info on that here: https://sofimarshall.com/real-time-remote-editing/
Good luck to you!