The contango drag on 3x ETFs is hilarious - good luck on your endeavors sir, I've got futures contracts for sale for your fund manager to buy.
what? which funds pay 3x dividends? All of the leveraged ETFs i'm familiar with replicate the 3x exposure with futures contracts, which do not pay dividends. the drag exists when these futures contracts are in contango, where the back-month is more expensive than the front-month. The leveraged ETF pays that drag every time the fund rolls to the next futures. Nothing to do with borrowing costs.
This is also the reason why USO trends down long term, regardless of the spot price of oil.
Leveraged ETFs are very dangerous animals, though.
UDOW lost 17% in 2020 while DIA went up 8%.