Where is the scan that says Beerus can wipe out 1/5 of the universe at full power, and Whis is a reality warper ?
There isn't anything that says Beerus can wipe out 1/5 of the universe directly. That idea's based on a mention that Beerus didn't destroy the Kaioshin realm because it wouldn't be appropriate to blow up the realm of the gods like that, so he just sealed the old Kaioshin in the sword instead, and apparently the Kaioshin realm is something like 1/10 the size of the mortal universe, so people have figured "if Beerus can destroy something the same size as 1/10 of the universe, he could do the same to 1/10 of the universe."
"Reality warper" is a fan term with an extremely unclear definition (lately it seems that a lot of people have plopped it in as a level of power distinctly above anything more "normal," as if someone who's a "reality warper" would automatically win against anyone who isn't... but logically it should only refer to the
type of powers someone has, saying absolutely nothing about their strength or whether they'd be able to do diddly squat against someone vastly more powerful but with more "normal" abilities) and I doubt you'll ever find any statement "confirming" something along those lines.
That said, being able to rewind time 3 minutes probably qualifies as "warping reality" to some extent, considering that he literally makes everything that happened in the past 3 minutes... not happen... and yet people still remember some of it, apparently. And it's not actually time-travel as nobody "goes back" in the Trunks/Cell sense (only one Whis/Beerus/Goku/etc. is present after the rewind), and no split-timelines are involved.