The “mistakes” idea is the Darwinist’s “god of the gaps”. They used to tout “junk DNA” as proof of evolution - until it was discovered that it isn’t “junk”. Now they have just moved on to something else.
BTW, there is no reason why God has to create things with features that we find satisfactory.
“we find satisfactory” Good point! Who are we to tell God “THIS would be a better design”