This is frustrating because I cant remove my full bitcoin balance cause when it shows the available balance, I type that in and all is good, but by the time I click withdraw the damn available btc amount changes lower than my inputed amount and says insufficient funds. I dont remember it doing this a not too long ago.
here we can find the factors of the problem you are facing, the key is in other cryptos that you hold. Of course this is very clear if when you withdraw everything using BTC, the amount of balance automatically decreases. first you haven't made another crypto exchange to bitcoin. therefore when you enter the amount of bitcoin there will be a notification that your funds are insufficient.
try selling off the rest of the crypto being traded first. and collect on the same assets, for example enough with bitcoins. not separated from other cryptos.