Yes, I think it shuld be sufficient. I used some 24 awg because it came in a longer spool and was available. Marklin says you only need 28 awg I think. Their wires supplied with the Cs3 look like 20 or 22 awg. becaue it has a larger digital booster, and they send all the data to the tracks. The C track wired terminal connectors look like 26. The wires from the MS2 track box, and former M track turnouts and signals look like 28 or 30.
Thicker is no problem, and better for long runs. All of the screw terminals on M83, M84, etc. accomadate 24 awg.

This is incorrect. Please read the "Wiring Basics" chapter of the Large Manual, Märklin No. 03093. 18 awg (0.75 m^2) is recommended for both the main track and accessory buses. Feeds to the track from the main bus can be short lengths of lighter gauge wire.

I use 0,75 mm square main connect and shortest way to connect the track from the main are 0,25 mm-0,34 mm square.
This should be enough since we are writing about power feeder 60041 which do have 3 amps output.
For bigger trains like scale 0 and 1 needs thicker wires because of the power feeder 60101 which does have 5 amps output.
There is also two difference type of the wires...standard copper and tinned.
Tinned wires are more expensive and are use in the industry for greater requirements.

My take on digital wiring: 24-22 gauge from decoder to switch, signal etc (short runs); 22-20 from decoder to CS (long runs) and 20-18 from CS to track power connects.
(NB I have all M track and vintage accessories)