I'm using a Bullseye/Blokhead hotend fan duct on my Ender 3 v2 and I have trouble getting to the PC4-M10 Bowden connector on the hotend without dismantling the duct. I've designed this 10mm socket wrench with an opening for the Bowden tube. You can use either your fingers or a 10mm wrench with this piece.

I printed this on its side to prevent shearing when wrenching on the Bowden connector. I also printed with max perimeters for more strength as well. I used the PrusaSlicer 2.6.0 alpha with organic supports to hold up the inside of the socket, but you can probably get away without that extra support. You will need a support for the other end of the wrench though, since it prints in midair when the piece is on its side.