Upgrading from ds215j to 218 play or +

I would like to upgrade my actual NAS (ds215j) to 218play or 218+.

The main reason for this choice is that using plex from my ipad o iphone (sometimes also from my chromecast / Amazon key) get stucked saying “the server is not powerful enough to convert video”.

Obviously if there is a solution, I will be glad to ear it. :smile:

What do you suggest? Actually I use the NAS just to store personal file and to use PLEX.

Thx in advance!