More can be said about this but I'd recommend reading this thread with an answer by /u/Georgy_K_Zhukov and also this answer by u/commiespaceinvader

Just to add something here

their own failures (Montgomery)

By any objective standard, Montgomery was a successful and competent officer.

I know of not one single example of where Rommel got the upper hand over Montgomery, with the latter prevailing over the former from the border of Egypt to the bocage of Normandy.

So while it may indeed be the case that Rommel was mythologised by the allies to justify their own shortcomings, these shortcomings - from the British perspective these would be typified by Ritchie's failure at Gazala, and from the US perspective would include Kasserine Pass - pre-dated Montgomery's appointment to command of the 8th Army or were otherwise outside of his control.