It’s scary to learn about a MALs diagnosis when the artery that is compressed is one that supplies oxygen to all your firm organs needed for digestion. You have many questions, which is exactly how I felt at first as well. I was afraid.
But it sounds like your symptoms are noted early enough to allow for careful, thorough evaluation.
To educate yourself, you may want to join the MALs Awareness Facebook page. I have learned so much from them through the brochures in their files and the discussions. They have a list of MALs docs as well.

They say MALs is a congenital anomalies, meaning a person is born with it but signs and symptoms may not manifest for many years.

Body position and breathing affect compression. Body position of comfort seems different for each person, but many report knees to chest or forward is best. I relieved stomach pain my whole life by laying down on my side with bent hips/knees. Also, compression is worse with expiration.

My symptoms: pain with first bite of food starting in esophagus, then stomach, pancreas, gall bladder. Nausea and early fullness. 20 lb weight loss. Dry hair, nails, muscle and joint pain all were bad but got better after lap surgery and use of acid supplements 1 year ago.
Also many strange issues: lightheaded, pounding heart, low blood pressure, brain fog with speech and auditory processing difficulty (More noticeable to me than other).

My evals: ultrasound of celiac artery with images in inspiration and expiration to measure blood flow velocities. The higher the velocity, the more the compression. CT of abdomen to see actual anatomy.

My coping strategies: very small frequent meals, laying in position of comfort immediately after eating. I tend to take deep breaths and hold to promote blood flow through the celiac artery. Trial error with testing what foods work best. I don’t
have enough stomach acid so can’t digest protein but I take an acid supplement when I eat meat; lots of odd symptoms improved after I started that. Some people don’t tolerate veggies, some can’t eat sugar. Seems to vary greatly. I do not recommend trying acid pills with out guidance of a specialist, which I had. Some people have too much acid. I had tests that suggest mine was low.

Surgery: I had lap surgery with arcuate ligament release and removal of some of the nerves. All symptoms disappeared except stomach acid limitation so I still take an acid pill with meals that include protein.

There seems to be 2 debates with MALs. First is vascular vs nervous systems issue. Many who have ligament release but nerves not addressed continue to have more pain after surgery. Leads docs to consider this as nerve compression issue. I think it’s both. Second, lap vs open surgery. Some with lap have symptoms return later with scar tissue. Dr. Hsu from Connecticut is the most reputable surgeon (maybe arguable for those who disagree with his method) and he removes the ligament all the way to the spine so people do not have symptoms return. I had Dr. Kendrick from Mayo and I feel satisfied with results but still use some of the same coping strategies, maybe out of fear or habit, or need. Not sure why. I avoid sitting where compression is worst for me, even after surgery as it seems to irritate surgical area.

Evaluation/intervention for MALs is a long journey with more questions than answers. I wish I had joined MALs awareness support group before my surgery. I have learned to have patience, educate myself, take 1 day at a time, rest frequently, and take deep breaths to relax and calm myself. It’s challenging but worth the difficulty because the gratitude for health experienced later is the greatest feeling.
My thoughts and prayers are with you!