High Cp vs Type Effectiveness

Level/IV?

As a rule of thumb, the difference in atk between lvl 20 and lvl 30 mon is roughly 1.2 which suggest that type advantage is more important. However this also depends on the moves, in your example DT/O is superior to AS/AA so the difference is even smaller. Another thing to consider is that lvl 30 is 50% bulkier than lvl 20 so in a solo raid that can make a big difference.
Finally, use Pokebattler to get a definitive answer.

You can easily check this using pokebattler.

Level 20 AS/AA Ray: Time to win 184,9s Power 54,9%
Level 30 DT/O Ray: Time to win 162,2 Power 87,4%

The level 30 DT/O Ray wins hands down.