How do I ensure best signal performance when using a 2.92 mm (K) connector that is compression mounted on my PCB?
To get any reasonable performance out of this "compression-mount" connector, you need to contact its manufacturer and request drawings of fan-out pattern for their product, a real PCB test layout with full manufacturing information for stack-up, and request network analyzer data from them. If you want to get anything at 20+ GHz, you better get a 3-D electrical model for the connector, and have a good CAD tools that can model your PCB elements and traces. Then you would need to try different layouts three-four times (either three-four different test coupons on one board, or several board spins), and run your test coupons on good network analyzer until you get acceptable performance.