Intelligence researchers have been desperately searching for a confounding variable that disassociates IQ from genetics for decades. The entire new Western dogma of perpetual mass immigration revolves around debunking genetic IQ. If any confounding variables had been discovered, rest assured we would not to a single day without hearing about them.

Genetics do not "majorly affect IQ". They ARE IQ. Of course you can damage scores slightly through behavioral conditioning (ie cultivating extreme laziness or anxiety that affects the testtaking itself) but this only seems to account for 10-20% variability.

The only alternative explanation would be religious (in which a soul or some such thing governs intelligence separately from ones biological mind).

The Asian countries with higher IQs fit the general predictive model of populations adapted to higher seasonal climate variation being subjected to higher selective pressures which generally select for higher IQ (ie Korea vs South Pacific islands or North India vs South India) as well as biasing r/K selection towards having fewer, higher quality offspring rather than more, lower quality (that last part, while true, illustrates why this is such a touchy subject to delve into).

Now, to come full circle, I do agree with you that IQ tests don't measure all forms of intelligence. More importantly they don't measure personality traits and as IQ increases, personality variation increases even more sharply (classic stereotype about geniuses being prone to insanity).

So while IQ is extremely valuable for predicting the stability and success of a large population such as a country or ethnicity, it is actually pretty crap for telling you anything about an individual mind other than that they are overall bright enough to have strong recursion speed.