OpenWRT isn't fully baked on RPi4. I've been playing with this community build: Rpi4 < $(community_build)
Also, I recommend using a USB enclosure that has two USB connectors like the one that ltefix.com sells (unfortunately, they are shut down right now). The spec sheet for the 7455 says the maximum current draw is 1.5A which is 4.95W. USB3 supplies 5V a max 900ma. Even assuming a 100% efficient 5V -> 3.3V conversion, USB3 can only supply 4.5W.