funding fees is a total of the capital you intend to use to trade not even your margin alone
I do not really understand this, but this is not what funding fee is. Funding fee is the money added or deducted to or from the money traders used to open a position at a given time like every 8 hours, 4 hours or 1 hour for the coin derivative price not to have huge price difference from the spot market price.
funding fees are very volatile and could drain capital easily even though the essence of funding fees is mainly to maintain the price of perp contract and keep it aligned with the price of Bitcoin in the spot market at any time.
This is true, but it is more volatile for some altcoins and not that volatile for good coins like bitcoin, just just that position holders can not go for it because over long time like 2 years, small amount of money can accumulate into a big amount of money.