But, no one has tried to explain to me how macroevolution can happen without Darwin’s survival of the fittest.
Survival of the fittest is more a popular slang term than anything really related to the Theory of Evolution. It is somewhat misleading since it sounds like it is assigning some value or quality criteria, critter A is Fitter than critter B.
Actually, it's Natural Selction. There are two basic parts to the Theory of Evolution. One is that change happens all the time, that there are mutations that go on all the time in every critter.
The second part is Natural Selection. Every once in a while one or more of the random changes might give one critter an advantage in reproducing. Maybe it can feed more efficiently and so spends less energy eating and more energy screwing around, or maybe it's faster and so less likely to get eaten and so has more time to screw around. That critter has a better chance of living long enough to breed and so pass that trait on to future critters.
But the Theory has changed much since Darwin. There is still no such thing that I have seen as Macroevolution. So far it just looks like lots of time and lots of little changes. There is the newer modifications to the Theory to explain newer evidence, for example, the long periods with little change followed by short periods of great and abrupt change.
So it's still the Theory of Evolution but if Darwin returned today he'd have a bunch of studying to do to catch up.
Aslan is not a Tame Lion