Here's the HU upgrade for my 2005 4Runner - non-JBL but I included a link to the JBL Metra wiring harness. If memory serves the stock wiring harness has both JBL and non-JBL connectors. The Metra harness just simplifies things as well as ease of installation.
Aftermarket Head Unit - Double-Din:
Alpine iLX-W650 7" Mech-Less Receiver Compatible with Apple CarPlay and Android Auto
https://www.amazon.com/gp/product/B0..._title_o05_s00
Aftermarket amp for Alpine iLX-W650: (bolts on behind HU)
Alpine KTA-450 4-Channel Power Car Amplifier, Compact PowerStack Amp with Bracket, Ideal for iLX-W650
Amazon.com
Metra 70-1761 Radio Wiring Harness For Toyota 87-Up Power 4 Speaker: (non-JBL) optional
Amazon.com
Metra 70-8117 Factory Amplifier Harness for 2004-Up (Toyota Vehicles with JBL Sound System) optional
Amazon.com
PAC SWI-RC Steering Wheel Control Interface SWI-RC-1.
Amazon.com
I'll save you the grief of trial and error looking for a proper CarPlay compatible USB extension (THIS ONE WORKS):
*I installed it where the cigarette lighter used to be in the shift console.* also a great location for a bass control knob for a sub.*
PAC USBDMA1
1-foot USB cable extension — great for car stereos with rear USB ports
https://www.crutchfield.com/p_541USB...C-USBDMA1.html
Now, a lot of these newer model head units will lock you out of certain features to keep you from wrapping yourself around a telephone pole goofing around with settings while driving. It requires a connection to the parking brake wire - yellow/blue or yellow/orange (can't remember) I ran this along with acc power to a 5 pin rocker switch to get around this as simply grounding the wire once isn't enough. Fit perfectly in a shifter console blank.
Nilight LED Light Bar Rocker Switch Stereo Rocker Switch 5 Pin Laser On/Off Switch 20A/12V 10A/24V Switch Jumper Wires Set
https://www.amazon.com/gp/product/B0..._title_o00_s00
*Here is a cheaper alternative to Alpine* It has an internal amp.
I installed this in my 5th gen 4runner:
Boss BV800ACP
Digital multimedia receiver
https://www.amazon.com/BOSS-Audio-Re...P9J/ref=sr_1_1
I did a lot of research before pulling the trigger on this particular setup and it paid off with a quality retrofit stereo system that kicks azz!
Good luck with your audio build.