Should I have a gap after Invisalign? Is composite boding the best way to fix it? (Photos)

That depends on the plan you finalised with your dentist. As you said, 59 trays, so it meant that it is the comprehensive plan (unlimited trays for three years or five years). In my practice, when I go for a comprehensive package means full correction, and I give the result accordingly. But many doctors charge an amount for certain trays (eg. in your case).
So it's my advice to talk to your dentist about your plan, you approved.
I am an orthodontist and I never advice bonding for space closure. I always achieve by orthodontic treatment (braces/aligners) only.
In photo, I can see your smile is not perfect because of your central incisor is not well aligned and tilted also, so its my advice to correct that.
REMEMBER: Tilted tooth correction is more difficult than alignment.