Against a large portion of the cast, forward throw, immediate backdash, immediate jump in attack/empty jump is as close as Ken gets to a universal safe jump set up. You can mash the backdash during the throw animation to have it come out on the first frame every time and you can hold up forward during the dash frames to get the immediate jump in.
The empty jump setup works against some 4 frame reversals and almost all 5 frame reversals.
And with the exact same timing, you can jump and attack for a safe jump against all 6 frame reversals and upwards.
This setup allows you to OS almost with no fear whatsoever. You can add ambiguity to your mix up by using an EX tatsu to cross up. It’s pretty much safe against all reversal DP attempts but it gets beaten by delayed DP’s, but then a delayed DP gets beaten by the original meaty safe jump, so its a strong guessing game for Ken.
For characters with 3 frame reversals (and certain characters with 4 frame reversals) neither the empty jump or safe jump will work, but you can still do a tatsu to avoid DP’s. If you get the timing right, you can cross up with an early air rh tatsu in the same way as you can with an EX tatsu, saving you meter if you think they are going to try the reversal…
Outside this, almost all of Ken’s safe jumps require manual timing to perform. The “slight step back, whiff a normal, jump in” is extremely common knowledge in the Ken community which probably explains why you don’t see any tutorials on it. But online, these setups are nowhere near as guaranteed as they seem in the training room. I practiced the timing for safe jumping in on Ryu for over an hour the other day, took it online and got reversal DP’ed over and over and over again…
Hope this helps a bit.