To add to Bozarth & SQLit, the present venting arrangement may be a
violation of code. I'd check with your Building Official / Inspector.

Use metal duct, a code requirement in many locations.

Use the most direct path possible.
Allow for clean out, particularly if you vent up.

Going "around a door" isn't clear.
If that means running the duct up and over, heed Bozarth.
TB