Heat oil on saute in 6-quart electric pressure cooker. Cook ham 6 to 8 minutes, stirring, until edges brown and meat 165°F. Plate.
Cook fennel and shallots 5 minutes. Stir garlic 30 seconds; add 1 cup broth and scrape bottom completely clean.
Add beans, remaining broth, thyme, and pepper. Stay below bean half-full line; lock lid and pressure-cook on high 35 minutes.
Naturally release until indicator drops, about 20 to 30 minutes. Open; check beans completely soft. If firm, pressure-cook another 5 minutes; naturally release again.
Discard thyme stems; carefully immersion-blend smooth, blade submerged. Add lemon juice and up to measured hot water if too thick to pour.
Taste before adding up to measured salt. If needed, rewarm ham separately in small skillet over medium to 165°F. Divide soup among six bowls; top with ham.