Yes. welcome to TS!
Ideal position in the room pictured above for a pair of mics alone would most likely be centered, halfway between the soundboard and stage. But you probably can't do that (openly). Second ideal position would be at the centered at the stage-lip or on-stage, but that might require combination with a soundboard feed if there are vocals or other instrumentation that is primarily only amplified through the PA system.
Recording from the soundboard location looks to be a bit far into the reverberant field, but may be the best practical bet. That's a perfect scenario for use of the
improved Point At Stacks method, which makes the best of a somewhat over-distant recording position with the use of directional microphones pointed directly at the PA speakers located on either side of the stage, combined with a spacing between the two microphones that is derived from whatever the angle between the microphones ends up being in that case. The narrower the angle, the more spacing between the microphones. You will need a microphone bar that allows for spacing adjustment. Here's a link to the discussion thread about this which includes an easy to reference table of microphone pattern, angles and spacing that makes figuring that out easy-
https://taperssection.com/index.php?topic=167549.msg2087409#msg2087409 Recording from the side is a gamble, but can work. The better proximity can pay off in terms of greater clarity (or not) depending on the radiation pattern from the near-side PA, but the imaging may be lopsided in terms of the band on stage and the audience distribution. If you do decide to record from there, or any off-center location, point the microphone array by ear, not by eye. Don't point at the geometric stage center or the far side in an attempt to counteract the off center position, doing so will only aggravate the panning imbalance. Setup using your preferred microphone configuration (when far off center it can help to use less angle between microphones offset by somewhat more spacing between them than you might otherwise typically use) then close your eyes and turn the mic-stand to face toward the apparent center of the band once they start playing, regardless of whether that has the microphones pointing in a visually off-centered way. Most likely you will find yourself facing more toward the close-side PA.