Yea I don't see this being a software problem solved by another server. Sounds like the hardware on which you installed your plex server is too weak to handle streams and/or your wifi is too slow to handle the streams. You should play back content and then load the plex server in your PC web browser and see if it is transcoding or direct streaming. If it's transcoding, then your issue is going to be that your server can't transcode fast enough (most likely).
You can try emby, but it has all the same limitations. You cannot magically transcode a format for no CPU or GPU resources. If you're using a laptop for your server, its most likely unable to keep up as it won't have a good GPU to help transcode via hardware and laptop CPUs are generally weaker than desktop counterparts - as they're made to focus on low power and long battery use not high powered computations.
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