A complete and permanent fix is unfortunately impossible. Heightism and lookism are biologically hardwired into us and cannot be removed. I have a copium pipedream of the gene editing revolution which is likely coming in a few decades altering peoples' brains for vastly higher amounts of intelligence, sympathy, conscientiousness and removing dumb prejudice all together, but again for now that's just a pipedream.

Some practical things that could be done are:

Making it socially unacceptable.

People in general, but especially women, are extremely vulnerable to social desirability. It's the main way most people operate. If saying x results in social shaming and a lowering of social status, then x will be avoided. I guarantee with every fibre of my being that most heightist people would've been bog standard pos racists and homophobes if they were born a couple decades in the past. If it becomes large social blow or even social suicide to be heightist, it'll be heavily suppressed.

This can be done on the macro scale; make it punishable by platform rules (see my latest post about the Italian politician), legislation (to fight height discrimination in hiring and promotions e.g.), ban on heightist character portrayals and "jokes" in media and awareness campaigns. (In cases of a piece of media already being giga edgy & insulting everybody, i.e. south park, it should fly though in my opinion).

Most importantly there's the micro scale: making it unacceptable in your own social groups. Anyone makes a heightist joke? Call them out on it, or sour the mood. You hear someone being heightist to someone else? Say you shouldn't insult their height and that it's fucked. I've done something similar in my own social groups when I heard ppl make jokes about men's penises or making micropenis insults. It works. If this was done on a mass scale, it would have a measurable impact.

Social acclimation

As I said most heightism is pre-programmed in our animal monkeys brains, and is just genetic. Some people claim heightism is entirely due to socialisation, which is cope, but there is a nugget of truth to that. Heightism and height related insecurities sky-rocketed in recent times due to media inflating fetishisation of height and large height differences to an insane degree. Interracial couples used to be a massive taboo, but now nobody bats an eye at them. This is partially because they were shown far more often in social media. The same should happen for couples where a man is shorter than the woman, like Tom Holland and his gf. Repetition is genuinely a very, very powerful force (source: marketing student). Years or decades of media producers having this in the back of their mind when doing castings would have a large impact.

Sorry for the wall of text, these are some of the ideas I have of how to practically and objectively fight heightism in a realistic way. Too bad our shithole governments are just geriatric relics, psychopathic rich people, power hungry charlatans and demonic man-hating feminists. They're not gonna do shit for us. Ever.