[Pic. 1]: high tolerance in middle, normal version to left and right

The combo cap one is the normal version. The unneeded tolerances is in case the first one doesn't fit for you. The pull tab is pretty robust and lays flat against the case. Print with the pull tab flat to the printer bed so that no supports are needed.

Based on measurements from my own 2i2 and from reezzy's sketchfab model. Should fit most versions of focusrite with combo input though.

reezzy's model:
https://sketchfab.com/3d-models/sound-card-focusrite-ff919adab81c40f69646fc113539a9e7

Included step and fusion360 file in case anyone wants to edit. The main version is the one I personally use for mine and has perfect single hand push fit resistance. The 4th/final version includes tolerances that are unnecessary, but may help those with less than accurate print settings. Scaling the original cap would either make the inside or outside of inner ring incorrect, which is why I included tolerance version.

Possible idea: rotate the tab to the top and then attach it to the volume knob so that the cover is attached even when loose. Would reduce need to keep up with loose part.

Creality

Ender 3

No

No

.08

5%

Printed with a single perimeter and 5% infill so that it is quite flexible. Temperature of 210C nozzle and 60C bed works best for me with this specific filament. Sliced as step file in PrusaSlicer-2.5.0. 4 solid top and bottom layers, and a first layer height of 0.2. My layer height of 0.08 is excessive, and other typical layer heights should work fine. Random seam position so that the seams aren't clustered in a single line and mess up the fit. Printed the high tolerance version with 2 perimeters and 15% infill to make it less flexible. Speed of 15mm/s and travel speed of 100mm/s.