how much does it cost to hold commodity futures long-term?

let's say i wanted to buy some natural gas and hold it long term (2-3 years) in hopes of catching another spike from this low.

i see on my IBKR console, i've got the henry hub natural gas future contract for may, june, july, and infinite may. i'm assuming infinite may is the one i want to buy for holding long-term?

i was browsing twitter and it said it costs up to 6% per month to hold these contracts. that seems ridiculous and a recipe for losing money. is there any way to purchase these commodities (short of taking physical possession) that doesn't cost me 6% per month? thanks