I run a ds218+ as media server for my living room. It runs a stack of xxarrs and plex media server. It mostly streams direct, but does some transcoding when we’re on holiday.
I know I’ll have to update plex afterwards, but is there any reason i shouldn’t update this NAS to dsm 7.2.2?
Short answer, for your particular case, no. You will get an up-to-date OS, with zero negative effect in regards to your current software/platform requirements.