I ran a regular (exhaustive) optimization that took about 2 hours to complete.

I tried to run same optimization in CMAR mode by adding
OptimizerSetEngine("cmae"); code near top of code. Amibroker is estimating over 6000 optimization steps and calculating 3 days to run

What you are doing wrong is using CMAE when exhaustive optimization takes only 2 hours.

CMAE is for something that CANNOT be solved using exhaustive optimization.

The key word is "ESTIMATE". It means WILD GUESS. There is literally no way to guess the number of steps or time required to complete smart optimization. So it prefers to initially err on safe side (it assumes that things will go worse).

It could equally say: we have no idea how long it would take, because by nature of smart optimizer, it is impossible to know in advance. It is like weather, not predictable on the long run.