IT’S YOU VERSUS YOU
Mentally, you are never going to feel fulfilled or happy if you're constantly comparing yourself to others. It is not a healthy thing to focus on!
On another note, what really matters is progression, meaning if you are better than you were 3 months, 6 months or 12 months ago you are doing great. You need to find some satisfaction in that.
Ultimately, comparing yourself to other physiques all of the time can impact you negatively because we all naturally focus on the things we don't have. What I mean is, you may have great legs, but genetically your arms might be weak - therefore, you may focus on someone who has crazy arms. You may never have arms like them, but that doesn't mean you can't improve yours which is what matters.
For your own peace of mind, and to find enjoyment along the journey, please focus on yourself! So many people ruin their mental health up by obsessing over others, which is made worse by social media - don't do this to yourself.