TS-435xeu vs TS-431xeu
Yes, there is a noticeable difference between these models. The model number itself indicates better performance (35 instead of 31 series).
You will get 64-bit ARM not 32bit
4 GB SODIMM DDR4 (1 x 4GB) instead of DDR3
2 x M.2 2280 PCIe Gen 3 x1 slots
You can run VM, but it will not be as fast as 53D series which is also not the fastest, but tolerable
All of them will support 4k direct streaming. Transcoding would work on Celeron based model inside Video station app. Plex is a different story, but local streaming should be OK.
I hope this helps.