

Any low power device is going to struggle with video playback unless you’re doing direct streaming. The exception being the new Intel N line of processors that have capable enough GPUs to do the transcoding. If all you’re after is decent transcoding performance for H264/H265 video, anything newer than Intel’s 7-8th gen CPUs will do the job. $100-$200 used optiplexes and thinkcentres can easily handle this type of workload.
For reference: https://en.wikipedia.org/wiki/Intel_Quick_Sync_Video#Hardware_decoding_and_encoding
Most people go with either FreshRSS or Miniflux but there’s lots of options to choose from.
https://selfh.st/apps/?tag=RSS