Looking to Upgrade Hardware (Acer RL70)

I’ve had my RL70 for around 5 years or so running Kodi, and while it has served me well, I feel the need to upgrade. It has a Windows 7 install which boots straight into Kodi however it seems to struggle with HQ skins.

What seems to be the preferred choice these days? The majority of my content is HD 1080p and my current setup handles it fine however I’d like something which in future, can handle 4k.