If you do need another solution (which it sounds like it's working okay since it has a snap to hold it in place), our golden did better in a foam soft cone called Comfy Cone (amazon link, not an affiliate link or anything weird). He ran into everything in the plastic e-collar.
Stiff enough that he couldn't get around it, but a bit more forgiving in tight quarters. The plastic cones for large dogs are just so wide. It was so bad :C. I can't Imagine in an apartment.
Hope he feels better soon! He sure is a handsome boy (but I'm biased)
Edit: words are hard
We got our golden this cone when he has to have surgery, he liked it a lot more than the hard plastic one: The Original Comfy Cone by All Four Paws, Soft Pet Recovery Collar with Removable Stays https://www.amazon.com/dp/B002MVV194/ref=cm_sw_r_cp_api_glt_fabc_A65AQZAZ0MG9M45WZTV3?psc=1