Try installing https://moonlight-stream.org/ on the Steam Link. Uses Nvidia's GeForce Experience to stream from your PC; works a lot better in my experience.

It’s fine for games that don’t require super fast reflexes. I played 99% of Final Fantasy X on mine. The only things I needed to move to my PC for were the (infamously difficult to begin with) races. The Persona games also ran fine on it. But it’s worth noting that all of those are turn-based, so I’m not worried about a noticeable slight input lag. I absolutely wouldn’t use it for something like a shooter or fighting game where reflexes matter.

My fiancée actually prefers when I use my Steam Link, because it means we can cuddle on the couch while I play. So she doesn’t feel like gaming is coming “between” us like it does when I’m at my PC and she can’t snuggle up next to me.

I used to have really fucking bad sporadic lag, (I would dip to less than 1FPS for probably 15-30 seconds at a time, every 5-10 minutes) but a recent-ish update (in the past few months, though I can’t remember exactly when) fixed that. As far as I could tell, there wasn’t any weird network traffic on my end that was causing it; It was just the Steam Link failing to keep up every now and then. But whatever they did in that update resolved things, because it’s rock solid these days.

Ive had lag once using the Raspberry Pi variant and that was due to using a poor quality usb cable, it was under powering the unit. Aside from that it's been surprisingly fast on ethernet and WiFi.

I actually got very mixed results with mine. Ultimately the app version is just more stable for some reason. I did get periodic lag, but interestingly I had the most problems with graphically intense games. Steam link has absolutely no problem, if my PC can run it smoothly it looks great on the app too. But on the hardware version it struggled to keep up and I got periodic crashes. Weird.