Why YSK?
The first person who typed “should of” probably heard of it in real life that was meant to be “should’ve”, they typed “should of” online and readers thought that it’s grammatically correct to say “should of” which is in fact wrong and it became widespread throughout the years on Reddit.
I hope something could start to change.
English contractions are very hard and I have been trying to be better at them. For other users like me who struggle with English, text generators like the ChatGPT can help a lot if you ask them to correct for you and they will give you tips. Be careful if it is online one like ChatGPT though, it isn’t private!