How to set ETH transaction to execute when gas is low

I’ve heard people talking about ways of setting ETH transaction so that they execute when gas is low.

I have two transactions I’m trying to do. One is moving ETH from metamask to Trezor. Another is putting ETH onto Arbitrum using Trezor linked to metamask.

Is there any way to set these to execute when say, gwei is under 70?

Thanks!