I've been trying to figure it out, gave up on steam link entirely and just ran a 20 foot HDMI cable to my TV that I used steam link on, this is annoying. Fix it steam! Happens when steam is open, and streaming anything to any steam link device, I use it mainly for watching videos as I don't game anymore, so it's REALLY noticeable when everything bugs out, and stutters like crazy every couple minutes. Zero hardware change, I use a literal freaking steam deck as a steam link client, and my PC hasn't changed in years(I hadn't even updated my video drivers since 2023! I did an update on 1/1/26! problem persisted before, and after! In fact it was BECAUSE of the stuttering that I even bothered to do a graphics update because if it works, don't freaking fix it!). Windows 10, steam, 2080 super gpu, tried both nvec encoder(stuttered WAY worse when enabled, and without. I always use CPU encoding because it's superior in quality, happens with any setting turned on, or off, limited, unlimited, you name it, zero settings matter, it will still cause stutters every couple minutes of streaming videos.

what is the refresh rate on the host pc?
and the client?

if they are not the same, its may be capturing at a different rate than the client can display smoothly

check the streaming log to see what they are
..\steam\logs\streaming_log.txt

ex.
if host is 144hz, and client is 60hz, it wont be grabbing 60fps evenly, so frame pacing will not be smooth

having steam change the display res/refresh to match the client can fix it
on host, in gpu control panel, create the client native res on the host
steam -> settings -> remote play -> change res to match client