Two things looking at those traces:
The trim gives you around +/-20 ppm of variation. At 4 GHz that’s +/-80 kHz, far too small to see on the span you are using. Plus you have the resolution bandwidth set to 1 MHz, far too large to see changes in the kHz range.
Set the span to 5 MHz or less and dial the resolution bandwidth down to 5 kHz or so and then see if you can the see anything. Don’t worry if the analyser complains that it’s outside of it’s calibration when you do this (some will), you aren’t looking to make accurate amplitude measurements so that doesn’t matter too much.
The multiple spikes on the other board could be due to something saturating and so not giving you a clean sine wave. Try turning the Tx power down and see if they go away or reduce significantly.