It’s pretty much impossible to answer this without seeing your face, but in my opinion... jaw > hair > eye area IRL (in pictures, eye area undoubtedly is the most important thing).
If your features are all “average” as you say, that would likely mean that your features are in proportion. You don’t want to fuck with anything if you’re OK proportionally; to try to explain this... getting a jaw implant to increase width would make your jaw look out of place in comparison to your zygos / forehead. Vertically, you can get away with a taller lower third (balanced/equal facial proportions = aesthetic, taller lower third/shorter midface = more masculine). If your chin width is proportional to your lip size, your chin will look odd if you get an implant to make it wider. The shit I’m talking about is basically “facial harmony”.
A good example of balanced ratios / extremely good harmony is Lachowski.
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His mouth is open here so you can’t really tell, but his facial thirds are extremely close to equal and the width of his zygos/jaw/forehead are in proportion.
An extreme example doesn’t have “perfect” or “ideal” ratios and proportions would be brock lesnar. Even though his ratios aren’t ideal, his face is terrifyingly masculine:
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Jaw noticeably taller than midface, somewhat short forehead.
however, there are guys that don’t have “ideal” proportions yet dont look extremely masculine. Brad Pitt and Leonardo DiCaprio both have pretty short midfaces coupled with a tall foreheads.
balance is key, and if you really feel like all of your features “fit Together”, don’t do anything major.