Can lower eyelid laxity and space between eyeball and lateral canthus be improved upon?

Correctly positioning a lateral canthal angle is very challenging.  The most difficult aspect is placing the tissue sufficiently posterior so that the lower eyelid margin precisely hugs the corneal surface.  This is essential to properly move tears on the corneal surface.  Then the eyelid margin does not hug the eye surface, drying and vision disturbance is common.  When the problem is severe, corneal breakdown can occur.  The canthopexy is a relatively weak lateral canthal procedure done to provide support.  A canthoplasty is a much larger reconstructive procedure to reposition the lower eyelid margin.  Then needed, a canthoplasty can also be performed for the upper eyelid margin.  There are not commonly needed.  I have a vast experience performing these type of surgeries.  Getting the eyelid positioned sufficiently posteriorly do the eyelid margin hugs the corneal surface is fussy and requires a great deal of experience.  You will need a revisional surgery to fix your issue.  Please see an aesthetically oriented fellowship trained oculoplastic surgeon.

You likely have lower eyelid ectropion/retraction, which unfortunately can happen after transcutaneous lower blepharoplasty. There are scar injections that can help. Massaging and squinting exercises are also useful. If it persists after 3 months, may need to consider lower eyelid ectropion/retraction surgery. See an oculoplastic surgeon.

Without seeing you in person , it is difficult to say what would be
appropriate for you. You should go see a local surgeon for evaluation.