Botha received a gift decision over a very sick Le Banner. Jerome was suffering from a serious stomach ailment at the time of this fight but refused to pull out because of various reasons.
Every single kickboxer you listed would get KTFO by any decent boxer if they had 4 weeks to practicing checking kicks.
No, it takes ages to learn that stuff, a boxers legs would get destroyed by leg kicks, Loma is very good at kicking though, far better than Fury judging by the footage on youtube and I kick better than Claressa Shields, I got a green belt in Shaolin when I was 9, lol
Not to mention his ego got the better of him and he boxed much more than he should have. Jerome would have won that fight easily if he fought more intelligently.
If you have a boxer trained to sustain and defend low kicks and eventually giving some, plus occasionally mae geri, I think will make him a serious obstacle to any striker. Boxing cardio, movement, positioning, angles and hands are unique. But fur months are way insufficient, 24 will do the work which isn't really that much time.
The result is that kickboxing wins a one-on-one fight with boxing due to its wider variety of techniques. The kickboxer keeps their distance and uses longer-ranged kicks to slow down and eventually finish the boxer.