Slow Crank, No Start When Warm

Mopar Tim said

2 AWG Wire​

2 AWG wire has a diameter of 0.2576 inches (6.54 mm) and is commonly used for applications that require high ampacity, such as industrial equipment, heavy machinery, and large appliances. It has an ampacity of 115 amps at 60°C (140°F), 130 amps at 75°C (167°F), and 150 amps at 90°C (194°F).

2/0 AWG Wire​

2/0 AWG wire has a diameter of 0.3648 inches (9.27 mm) and is larger than 2 AWG wire. This wire is commonly used in power distribution and transmission applications, as well as for grounding and bonding. It has an ampacity of 135 amps at 60°C (140°F), 155 amps at 75°C (167°F), and 180 amps at 90°C (194°F).

Differences Between 2 AWG and 2/0 AWG Wires​

Attribute2 AWG Wire2/0 AWG Wire
Diameter0.2576 inches (6.54 mm)0.3648 inches (9.27 mm)
Ampacity (60°C)115 amps135 amps
Ampacity (75°C)130 amps155 amps
Ampacity (90°C)150 amps180 amps
Resistance (Ohms/1000ft)0.6240.393
The main differences between 2 AWG and 2/0 AWG wires are their diameter, ampacity, and resistance. 2/0 AWG wire is larger in diameter than 2 AWG wire and has a higher ampacity. Additionally, 2/0 AWG wire has lower resistance than 2 AWG wire.
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Tim where did you get that chart? There are all kinds of them, and "some disagreement" LOL. AC ampacity is not to be used for automotive. Also, FOOTAGE of the total wire matters

I'm not claiming this website is more accurate, but quite different results.......

https://jascoautomotive.com/automotive-wire-amperage-capacity-chart/
To the OP............2/0 is considerably more capable than no2. As an example, wire size goes (smaller to larger) 10/ 8/ 6/ 4/ 2/ 1/ 0/ 00 or same as 2/0.
As an example, "old school" no4 was normally front mount 12V cable in most cars. Older 6V were commonly 1 ga.