Cylinder number confusion

ChatGPT is frequently wrong when it comes to automotive items, especially diagnostics.
P0354 is a cylinder 4 coil secondary circuit failure, usually a shorted coil. Cylinder 4 is the middle cylinder on the radiator side of the engine as you indicate. The DTC sets when the ECM doesn't get the feedback signal from the coil(s) indicated. That is commonly from a failed feedback circuit in the coil. The easiest way to confirm it's the coil and not a wiring fault is simple, swap the coil with a neighbor cylinder. The code should follow if it's the coil. Remove the engine cover and in the middle of the left cylinder head you will find the coils. Remove the retaining bolts and lift them out and swap cylinders 4 and 2, Connect them up and start the engine. If you now have a P0352 you have a bad coil. One thing with Toyotas and Hondas are that they are touchy about replacement parts, I have seen aftermarket parts from quality companies cause problems on them that an OE part cleared up as soon as it was installed, as such I use OE parts on the ignition and control parts of those brands.

I've never used any apps so cannot say if any are better. I just keep attending training and networking with other techs and stay updated on the automotive repair items. Been doing the job hands on close to 50 years myself. There are a few folks I could point you toward if you really wanted to learn, but don't know of any apps.