I bought one of these 6years or so ago:
https://www.merlincycles.com/bike-tools-workstand-49075.html
There are loads of other vesions of the same stand with different names on them.
Some find them too unstable, but I have used mine at least once a week, often three or four times, since I bought it and it has been fine for me doing all types of work on road bikes, MTB, kiddies bikes etc.
I keep saying I’ll get a better one when it breaks. It hasn’t shown any inclination to fail so I keep going with it
I always clamp the seatpost