This is my adapter for mounting the Biqu H2 to an Ender 5 including an optional mount for a BLTouch.
I've added a "chimney" for cable management.

If you're also interested in the 5015 fan & duct, you can find the other files here:
https://www.thingiverse.com/thing:4900767

Printing:

Print the adapter, I've used PLA. Place it in your slicer so the BLTouch slot faces up. Supports are required only for the 2 countersunk holeson the underside, the rest prints support free.
The BLTouch mount needs to be placed on the top surface, so the adjusting hole prints in z-direction. No supports needed

Assembly:

If you want to mount a BLTouch, go ahead and insert an M3 bolt into the corresponding hole, so it pre-taps the thread (for easy installation later). It's supposed to be a tight fit, so give it a little force if neccessary.
Insert the 2 M3 hex nuts to the adapter before screwing the adapter to the extruder using 2x M3x12 bolts.
Screw the assembly to the x-carriage using the original Creality pan head screws (M3x16), 1x from the front below the BLTouch-mount. 2x from the rear of the carriage into the slot above and below the x-axis.
Fix the BLTouch to the mount using 2x M3 bolts, secure with nuts if needed. Munt the BLTocu-assembly to the extruder and adjust the height, so tip of the probe sits 3mm off the bed (use a 3mm allen key)
Get your wiring done and zip-tie it to the chimney.

Done!

Firmware changes:

Set your nozzle-to-probe-offset in the firmware (mine is X-33 Y+5) and do your z-probe offset config.