I ended up on Plex and haven't looked back, mainly as I have a lifetime Plex Pass and added family members as managed users so we all use it across multiple devices, remotely and of course use Plex Amp too!
We use phones/ipads/Apple TV/NVidia Shield Pro and native TV apps for accessing it and that is the key..
For transcoding, you do need either an iGPU (pretty much any intel made in the last 10 years is fine), or dedicated GPU.. I currently use an i5 1235U in my NAS, mainly for power consumption but previously used a GTX 1060Super which was overkill for the paltry amount of transcoding that was needed).
I have had dedicated streaming boxes, from Popcornhour through to Zidoo, but found their Long Term Support patchy and ultimately had to keep upgrading, which is where plex and transcoding came in, that effectively allowed the player/renderer to have an extended life when it's hardware/software limitations kicked in.
I do still try Jellyfin / Kodi every now and again, I was a long time user of Kodi, but just found it never supported all the hardware features that well and required more manual metadata handling, something Plex just largely works with perfectly, as did it pick up my SATIP box easily and allow live TV on the Plex Client (which is a bit janky, so prefer Channels DVR as the front end for live tv).