As I have posted this in reddit:
I am not sure if this is common knowledge already, but I thought of sharing it to the community.
Refer to image for references, taken from ifixit, disregard red circles, be extremely careful on doing this. You're own responsibility.
Required steps:

loose hinge, you have
As you know, joycon wiggle is a very common problem. Looking closely at my disassembled switch (while I replace the thermal compound, removing copper shim), I noticed the hinges, and thought of taking my chances.
NOTE: there are 2 pairs of hinges on a single rail, with this method, the adjustment is done towards to the hinge that holds the joycon against gravity (pushes the joycon towards you, better!) on each pair.
Et voila! The joycons against the rails are TIGHT as how its meant to be! No more wiggle, not as bad as before. As a backstory, my switch is one of the first releases.
Please let me know your results if you'll try it.
EDIT: Are these called latches or hinges?
EDITEDIT: I actually put electric tape on the bottom of the rails too (before). But do realise that with that method, you're basically pushing the joycon track AWAY from the joycon shell itself. Upon changing my joycon shell, I realised that that wouldn't be the best solution, as the joycon tracks are not that sturdy screwed on to it.
With this method, the joycon tracks of the joycon is being pushed against the joycon rail on the switch itself, just like how its meant to be (I believe).
I already have removed the tape from the bottom rails.
I am not sure if this is common knowledge already, but I thought of sharing it to the community.
Refer to image for references, taken from ifixit, disregard red circles, be extremely careful on doing this. You're own responsibility.
Required steps:
- You need only to remove the back cover (may void your warranty)
- Adjust the hinges (push against the yellow arrow, as a counter pressure, as you push the blue arrows outside the switch, these are the hinges that holds the joycon against the rails)

loose hinge, you have
As you know, joycon wiggle is a very common problem. Looking closely at my disassembled switch (while I replace the thermal compound, removing copper shim), I noticed the hinges, and thought of taking my chances.
NOTE: there are 2 pairs of hinges on a single rail, with this method, the adjustment is done towards to the hinge that holds the joycon against gravity (pushes the joycon towards you, better!) on each pair.
Et voila! The joycons against the rails are TIGHT as how its meant to be! No more wiggle, not as bad as before. As a backstory, my switch is one of the first releases.
Please let me know your results if you'll try it.
EDIT: Are these called latches or hinges?
EDITEDIT: I actually put electric tape on the bottom of the rails too (before). But do realise that with that method, you're basically pushing the joycon track AWAY from the joycon shell itself. Upon changing my joycon shell, I realised that that wouldn't be the best solution, as the joycon tracks are not that sturdy screwed on to it.
With this method, the joycon tracks of the joycon is being pushed against the joycon rail on the switch itself, just like how its meant to be (I believe).
I already have removed the tape from the bottom rails.
Last edited by Skanob,