Regardless, I implore everyone to follow the terms and conditions of their casinos and to make sure that they complete their KYC from the beginning so that casinos will not use the excuse against them later.
This is bad advice. You should only complete KYC initially in casinos that mandatorily enforce it like Roobet etc. If it's not mandatory, you shouldn't submit your KYC information unless they request it later on.
It makes no difference when you submit your KYC as long as you are submitting accurate information without trying to fool the sites.
It is silly enough. You can get KYC when you need your money fast and wait for a week or even a month until you KYC. You can get some problems with KYC and just lose all your money. The best way is to initiate KYC by yourself if it is possible. Of course if you want to gamble in this casino for a long time and you don`t plan to cheat.