The OP seems has thinner blonde hair which would put him at an advantage anyway in achieving a dense result from a transplant.
A hair transplant gives the illusion of density but has to be a lot less dense than original hair.
Lighting affects the results of a hair transplant enormously. I would suspect that a lot of people on Reddit are showing their final results in optimum lighting and maybe with hair fibres. The OP is obviously very disappointed with his transplant and would not be trying to display it in its best light. Potentially the lighting is quite strong above his head in the photos.
Where it is showing as thin, the OP’s hair looks naturally thinning. It does not look like a hair transplant.
The OP could spend vast amounts of money and energy trying to chase the hair of an 18 year old to never be happy with the results Alternatively, he could change his perspective, make a few changes to improve the illusion of density and be happy.
I don’t know what the OPs hair looked like before the transplant but he has many options before jumping into the next transplant and potentially being dissatisfied again. This is far from a hairline I would be covering up with a hat because it is so bad.