Anyhow I want to know that if we delete our posts ourselves, does it have a bad effect on our account and can we still get tagged or something or it is completely normal ?
It is your prerogative if you think that you've improved and you see that your past posts are shitposts but if you tried to hide posts where you cheat and its an evidence you just admit that you are guilty, accounts that changed hands are usually accounts that delete their posts to avoid being traced, but if you think that your only intention is to delete useless and no value posts I don't think there's harm doing that.