Just to add…
A safe jump hits meaty but not all meaty jump attacks are safe jumps. Also, you can’t safe jump vs shoryuken because when you attack in the air you are vulnerable for 3 landing frames. So test vs Cammy’s Cannon Spike (4f), Hwoarang’s DP (5f), Poison’s EX DP (6f), Lili’s EX Angel Knee (7f) and Kuma’s EX Frolicking Bear (8f).
Safe jumps vs techable knockdowns are extremely risky as the defending player has a large window to tech. If they slightly delay their quickstand by 2-3 frames they’ll be able to jump out as your jump in won’t be meaty anymore. So that’s why people usually safe jump off untechable knockdowns (throws, sweeps, ground/wall bounce, Supers etc).
You can whiff normals/throw/specials and use dash/backdash/jump/taunts to get an “automatic timing”. Those types of safe jumps are the most reliable ones since you don’t really need to time anything. Safe jumps with “manual timing” (where you need to walk a few steps or wait 2-3 frames before jumping) are not as reliable because the timing is easy to miss. The timing of safe jumps can be very strict. And if you jump a couple of frames too late it can mean 50% of your ass in this game.
Don’t get your hopes up, not every character has an ideal knockdown that allows for automatic safe jumping. But they still do exist. They are just harder to pull off and more rare than AE.
Finally, a safe jump setup alone is not good enough because of roll recovery, so make sure you can “fake safe jump” and cross-up the roll instead. And ideally have a safe jump setup vs roll recovery as well. Though I admit I’m not sure if rolls can be delayed like quickstand… I never noticed any difference in timing for rolls.