If I have 2 ready units, can I simultaneously attempt to conquer 2 separate battlefields?

No, you cannot simultaneously attempt to conquer two separate battlefields with a single standard move action.

According to Rule 143.3.a, when you declare a standard move for multiple units, their destination must be the same. Because a standard move requires all units involved in that specific action to move to the same location, you cannot split them to target two different battlefields at once.

If you wish to conquer two different battlefields in the same turn, you must perform separate move actions (assuming you have enough ready units and the ability to perform multiple actions) or use other game effects that allow for movement or conquering.

As noted in RiftJudge FAQ #52, you can move multiple units from different origins to the same destination simultaneously, but the destination restriction remains absolute.