I am using 2200G with 4GB memory. I am running emulator, playing PUBG and lot more which are heavier than yours. So instead of spending more on memory for HTPC build, you can spend more on better PSU.
These are your choices, which you wanna lean that’s upto you.
Pentium or Ryzen
8GB or 4GB
Generic PSU or Antec
With Ryzen+8GB memory+Antec PSU you don’t have any money left for speakers. But with Pentium you will have about 1700/- for speakers.
Pentium G5400 | Ryzen 2200G
Asrock H310CM HDV | Asrock A320M HDV
Corsair/Kingston/Adata DDR4 8GB 2400Mhz | 4GB DDR4
Crucial MX500 250GB
Generic cabinet with PSU | Generic cabinet + Antec BP450p