Just a PSA:
One option is a used, 20 year old HP 8753E series. I had one of these. They work fine, but they are enormous, and you need to use a floppy disk or a GPIB to get data off it – not such a blast from the past.
I replaced it with what appears to be a Chinese knock-off of a Rhode-Shwarz portable VNA. Was $1700, IIRC, now is $1999. Perhaps tariffs, I suppose. Although there is a 4GHz version now that’s a bit cheaper.
I was prompted to take a chance on it after Shariar did a review.
I compared it to my 8753 (before I offloaded the 8753), and the performance was favorable. Hooray for 20 years of amortization of digital VLSI! It’s very small, which is also awesome. I like it quite a lot.