I use a puller... a simple tool with screw and pull arms. I have a couple sizes. From memory, the one that works on that joint is an AZ sourced generic tool. Set it up, put some pressure on the puller and if that does not do it, a light hit with a hammer always does. Even on ancient joints. Leave the nut on loose to catch the parts when they pop.

The trick is to pick the puller so it can fit, put pressure on the joint and not tear up the boot.

A pickle fork almost always works... but with collateral damage. No thanks!