Evolution is a population level process, selection is at the level of the trait or gene (depending on the type of selection we’re talking about). Say for example a gene that codes for a protein that protects against COVID, then there would be selection for that gene over time and over generations that could be established in a population with higher frequency (evolution).I had thought that a lot of the problems derived from the fact that evolution is a gene-level process, not an organism-level one, but that a lot of people get this backwards, and suddenly turn into proto-nazi social-darwinists dressing their biases up as science
Equally, it could be a trait like a more robust immune response to viruses that is a combination of genetic and environmental* factors which can become established as these genes are selected for along with the environmental factors (diet, hygiene, medical knowledge, etc.) which can cause a change on a population level (evolution).
In any case, the social Darwinists/eugenicists/Nazis take up the theory completely wrongly and use to justify whatever barmy ideas they had about race (whatever race is) so whether it’s at a genetic or a population level is a moot point as their logic usually falls down within seconds of comparing it with the evidence.
Evolution is a popular topic but it is hugely complicated (duh) and trips up the experts as it operates in a way that doesn’t come naturally to our ways of thinking. It is way more than natural selection, sexual selection, selfish genes, and speciation - and wrapping your head around it is challenging. And there is still much more to learn about it.
*Environment is also a frequently misunderstood term especially when we consider nature vs nurture debates. The environment is usually thought of as the external world outside of the body: other individuals in a population, the ecosystem, food and nutrients, etc. However, the environment is essentially everything that isn’t a gene. This includes all the thermodynamic noise, Brownian motion, epigenetic factors, physiological concentrations, neighbouring cells, etc. that a gene finds itself within. And this is different for every cell, let along every individual or species. Things like thermodynamic noise can have bigger effects early on in development (a single fertilised egg for example could end up not expressing as much of a protein due to temperature, changing the course of development for the entire organism) whereas things like social standing have more subtle long-term effects over a lifespan.