I would separate comparing them into 1. as draft prospect vs 2. as a player
As a draft prospect Corum would be much higher than Kyren because he's 10lbs bigger and significantly faster and stronger. Kyren combine 40 time was actually more disappointing than Estime's because Kyren was only like 195lbs and that size with 4.65 speed is considered quite slow.
As a player (admittedly I've seen way more of Kyren than Corum so there could be exposure bias) Kyren is better in most things you want from a RB (except measurable speed/strength) than Corum, plus Kyren has some 'special' to him that I haven't seen from Corum.
But we'll get to see them both on the same team now behind the same line, so..