Hey guys, I'm thinking about buying the gear to work on controllers, swap joysticks, etc. From what I've gathered, I'll need:

Adjustable soldering iron
Solder wire (thin with flux)
Desoldering braid + Solder sucker (essential)
Soldering flux (to make fusion easier)
Isopropyl alcohol (99%) (for cleaning)
Precision screwdriver + plastic opening tool

But hey, I don't have any friends or acquaintances in this field, so I can only turn to you guys for advice and product recommendations to get started. Controllers have been a passion of mine for a while now, so I'd love to finally get my hands dirty instead of relying on someone else 24/7

Through a lot of research, trial and error, modifying the inside to save space, making sure the bending/folding/extending still works, and a whole lot of broken wires i finally did it. A wireless ASUS Tessen!
I could of done a better job on the switch (it's smooth/flush so you don't even know its there).
It's not perfect but everything works, it looks like it isn't even modified, and the Bluetooth i can use from literally across my house!

Parts I used:

• 300mah Battery
• HiLetgo 1A 3.7V Lithium Battery Charging Board with Protection Type-C
• DC-DC 1.5V -> 4.2V to 5V Boost Converter
• Seeed Studio XIAO ESP32S3-2.4GHz
• Small micro switch
• Super thin flexible wire
• "skorokithakis" on GitHub for their "bluetooth-gamepad" repo (AI to edit for compatability)

If you do wanna do this i highly recommend it, some tips i would give is:

• To clear out as much space as possible inside the grips by removing some supports for the screw posts without removing them
• Remove the stoppers for the extending arms or the wires will get caught.
• Use some super thin and flexible wire for feeding through the extensions as it's super tight
• When feeding wires across the extensions, make sure to join directly to the 5v converter board and the other sides power input. If you splice between them the wires will break from pulling the device easily (This will save you a lot of headaches)
• Keep pressure on the center of the bridge so the wires don't curl.
• Seeed on the right, battery on the left.
• You can use the power input on the board instead of the bottom USB-C port to wire in the power as well

I also left my wiring diagram as well for anyone to use if they want to do this