During a game players jump while shooting. You could create the argument that consistency merits better results, but I personally see it differently.....
When you’re properly taught how to shoot, you shoot flat-footed (mid / close range) and the focus is placed on shot form mechanics. You’re told not to jump and to purely learn how to stroke the shot. The jumping element is taught once mechanics are solid... Then you would learn to elevate for defender-space and 3PT range generally requires jumping for not only space, but power. Shooting is ALL about mechanics, jumping is a variable that is taught as a necessity to create space and power. — KAT, Horford, B Lopez are 7-footers and excellent 3PT shooters. Watch them shoot wide open 3’s... They barely leave their feet because they don’t require power.
FTs don’t require power (after elementary age) or defender space. Adding a variable to any situation makes an outcome less certain. FT shots are flat-footed because mechanics are more guaranteed without the additional jumping “variable.”
PS - Rondo and Lonzo are not “decent” jump shooters. They are severely below average. Actually, up until roughly 2 years ago, you could argue that Rondo was worst in the league probably. RJ is a slasher / floater master. Average shooter. He can drop shots but I’d argue praising his shooting.