The preface this I’d like to say that in a way you’re looking for an answer that doesn’t exist (ie a surefire way to deal with divekick mixups).
Essentially if you are having problems with Rufus sitting in range and pressuring you it’s because you are now playing HIS game and HIS bread and butter. It’s like asking, “how do I deal with all these Akuma mixups after knockdown?”.
So answer no. 1 would be: Don’t play that game with Rufus. You don’t need to watch “The Tokido Formula” to understand basic strats vs Rufus. Instead watch how Tokido actually plays. Generally he starts out playing the game at distance. Why? Because we have fireballs/air fireballs. Rufus HAS to find a way to get in, the pressure is on him. Meanwhile in the beginning you will usually be looking for Rufus to make a mistake for a hard knockdown, at which point you can harass him with mixups.
Whenever Rufus gets in close and starts mixups on you you have TONS of options at your disposal. You should be exercising all of them to keep the Rufus player guessing so he doesn’t get free mixups. The most important ones are:
-OS crouch tech with MP
-Mash DP (99% of the time use LP)
-Backdash out
-Mash teleport
Also realize that Rufus and Yun’s divekicks both have to hit from a certain height to be effective. If they hit too high and you block you can usually just mash out crouching jab (against Rufus). I believe against Yun you can grab him for free, but don’t quote me on that.
You can also jump back and fierce punch etc. Watch some top players to get a sense of what they do. Of course I’m not saying to just use all these options all the time, good players will look for them/bait them out and punish them HARD. But the alternative of always doing nothing/crouch teching gives the opponent an easy guessing game. Watch how, Eita plays for example. He’s never afraid to mash out DPs early because he’s putting his opponent on notice that HE WILL DO IT, which is vital against a pressure character.
The last thing you should be doing is always waiting to react to Rufus’ divekick (unless its from a jump in). On pressure, like you said, reacting is hard to do, and you don’t want to be that close anyway unless you are pressuring him.
Yun’s divekick is much easier to deal with. His divekick has worse priority, a height restriction, and is much easier to react to. He can’t keep constantly pressuring you with divekick like Rufus, he mainly uses it to get in. Standing light kick works great, as do other standing normals, even on reaction.
Hopefully this helped you out.