Choosing a HDHP with high, unavoidable health expenses

Hi, I recently started a new job and I’m trying to make sure I understand the pluses and minuses of the different choices. I’ve never had a HDHP before but I think the one I’m offered may make sense for unusual reasons:

My situation: large, unavoidable Rx expenses ($20k before ins) and medical expenses ($10k) in 2023. PPO plans through work with a big network.

HDHP: $1500 deductible, then 20% coinsurance until $4000 OOP max.

Non-HDHP: $500 deductible, then 30% coinsurance for medical until $7600 OOP max. Rx copays would be about $750. About $1400 more in premiums and lack of HSA contribution.

I ran the numbers and both plans are not far apart in what I would expect to pay over the year. However with the HDHP I would hit my OOP max basically a couple months into the year and everything in network after that would be covered at 100%, so if I had any unexpected medical expenses later in the year they would be a non-issue.

I think the HDHP makes sense but I wanted to get perspectives because it goes against the usual “HDHPs are for people with modest controllable medical expenses” advice. The OOP max is so much lower than with the non-HDHP, it seems to make sense for people with very high medical expenses too.

Anyway please let me know what you think!