we don’t have to explain every feature of the world around us to be certain that evolution exists. Entropy swirls in eddies and waves, so there are some counter-selective remnants that persist, as a lot of reproductive success is blind luck, especially for small populations. Dig hard enough and most things can be explained, but for the majority of species out there, it’s easy enough to chart their evolutionary history, and getting easier as we accumulate more knowledge about everything.
But the general principles of evolution are absolutely concretely real. It should not be forgotten that it is not just genes that are responsible for heritable variation, but also the way that those inherited genes are expressed. The control of genetic expression in future descendants of a cell can be modified by changes to the genes themselves or changes to the gene packaging material (the chromatin) or changes to the environment that favor certain expression combinations or patterns, etc. Evolution happens in many dimensions, and there is a gathering swell of evidence that some environmental factors can have a strong influence on future gene expression in descendants. This is the modern field of epigenetics, and it is turning some previously long-held tenets of the central dogma of evolution on their head (not dismissing them, but putting them into a more generalist, comprehensive background). Like Einstein did to Newton.
find and read some Eva Jablonka if you are interested in this.