Ahh I love Plex server. I run mine from a standard midi-ATX using an Octacore Ryzen 7.
The key thing is make sure your machine has enough resources because if it has to transcode then this really saps whatever machine you run it on. If it’s 1080p to 720p or lower then this isn’t so bad but if you have 4K material and you’re transcoding then you’re better off encoding directly to 1080p.
Also, if you want to go on holiday and watch content from your Plex server whilst you’re away then check first what your upload speeds are. I get about 40mbs down and just under 10 up, This is not quite enough to stream 1080p to your caravan in Cornwall meaning you’re transcoding again.
Useless Plex fact that I didn’t know until I tried doing it - apparently you can’t stream HDR content to your own TV (eve if it’s perfectly capable of receiving HDR content) unless your able to fully utilise the audio in however many channels it’s coded AS WELL.
So if you have HDR with a 7.1 audio stream then Plex automatically transcodes it to SDR meaning you then get washed out colours and a lower bitrate. Very frustrating for movie lovers!