Same problems here unfortunately, what other software did you buy?
No solution yet, I have it as well… (using plugin version 1.5.4)
Raspberry Pi 3 is a good option if you want a cheap system, but be aware, MP4 video’s could load slow and maybe show hik-ups…
Intel NUC is a very good option if you want to keep cost low but be able to play any content smoothly: https://www.intel.com/content/www/us/en/products/boards-kits/nuc.html
And if you want to go pro/industrial, you should check out Quanmax, a hardware manufacturer specialised in digital signage devices: http://www.quanmax.com/site/solutions/digital-signage/ We use these in our company.