NETs: Scheduled for small intestine resection: What to expect?

I was diagnosed with NET 2 weeks ago. I had symptoms of obstructed bowel which led to a CT scan showing a tumor in mesentery, followed by a PET/CT DOTATATE scan, then a CT with contrast. Also had a colonoscopy. The results showed a 3 cm mass in the small intestine and an adjacent 5 cm mass in mesentery, both withe DOTATATE uptake. Uptake in the retroperitoneal lymph nodes Oncologist says it’s Grade 4. No information on the Stage. Things are moving pretty fast bc of results showing obstruction in small intestine which could turn into a crisis. I am seeing doctors at Johns Hopkins. They started me on Lanreotide March 22 and I am scheduled for surgery next week on March 30 to remove the tumors and relieve the obstruction. This involves a small bowel resection.
I am quite worried about all this. Especially because it tuned out that this condition predates 2015 so although it is slow growing, it’s been growing for a long time and is now quite big. A CT scan in 2015 showed a 3 cm mesenteric tumor but no one noticed. Plus my brother died of NET in 1999.
I would appreciate some feedback on experiences with small bowel resection. The surgeon is telling me that there’s roughly a 10% chance I’ll have permanent diarrhea and also if he finds more extensive small bowel involvement that he may have to remove so much bowel that I might need to be feed via a port. Has anyone had experience with this?