International student (F1 Visa) looking for health insurance guidance for my newly discovered tumor

tldr in bold

I’ve never had to actually use health insurance before. I would just pay for it as a student. Never been to a hospital either. But a month ago I went to the ER for abdominal pain and a CT scan found a huge mass in my abdomen. The description says it seems nonmalignant. Possibly a cyst, sarcoma, desmoid tumor but they won’t know until a biopsy/surgery. The surgeon at the ER told me it would be “impossible to manage this out of pocket.” But didn’t get into specifics. Upon consulting a couple of contacts who are doctors they say it is likely a desmoid tumor. Upon reading up on desmoid tumors, they can grow aggressively, invasively. So this may be a lifelong issue to maintain

I’m 36 M. Unemployed but with personal savings to cover my first year of school, and borrow money from a sibling for my 2nd year of graduate school at UTMB Texas in September. I reviewed their student health plan. Is a 20% coinsurance after deductible good? I’ve read that student health plans offered by the university are generally bad. How can I assess if a plan will be sufficient for the treatment I will need? And the best compared to others? The yearly cost for this plan $3438. I could call my university to get more info but I don’t know if they would be honest about it since they’re selling it. Will I be ineligible to get treatment for this “mass” since it’s a prexisting condition?

I’ve also read that my visa makes me ineligible for coverage through healthcare.gov, but that enrollment periods open later in the year anyway?

I’d really appreciate if if you could give me any advice and pointers. I’m happy to call places and read stuff, but I want the best and most accurate info. The stuff I’ve heard about the US health system makes me feel a bit helpless