Sort of. The plans we've had from at&t for the last 5 years included only 15gb of hotspot usage along with unlimited mobile data.
Seems like a fair amount of hotspot data except we live in the sticks and mobile has been the only Internet option.
On the upside were weeks away from gig speed fiber being installed to the house.
I'd replace the post.
The foam might work for a hot minute but I'm not even convinced of that. I'd think the stress from the weight of the gate will cause it to fail rather quickly.
If the hollow is up in an area where the hinges attach you might split the post with the foam expanding as it cures.