Question about HSA’s

I was looking into HSA’s but I’m not sure if I am fully understanding how it works. Here’s my current situation:

I have insurance through my employer that meets minimum coverage requirements. I pay about $140ish a month for premiums. The plan, however, kind of sucks for me because it has a point of sale prescription model and I require a few expensive medications or rather can’t get the medications that would work better for me due to the out of pocket costs.

I am a type 2 diabetic, insulin dependent. I spend about $150 on prescriptions a month, with about $115 of that being reimbursed by my insurance provider.

Additionally, I’m on an insulin pump, and because I got it this year, I’ve met my $2000 deductible. I typically spend $10-20 a month on pump supplies since I’ve met my deductible. I have no clue how much I’m going to have to spend next year when my deductible resets.

I see my primary care doctor 2-3 times a year, endocrinologist 2-4 times, psychiatrist 2-3 times. All are $40 copays ($240-$400/year).

So basically I’m just trying to decide if it’s worth my opening an HSA. There are no better options for me insurance wise, so my thought is to try to claim some tax benefits from the costs I have.

So if I understand right, I could use funds for the non refundable prescription ($35), the copays, and pump supplies? $285-$455 a year? Possibly more depending on the cost of my pump supplies prior to the deductible. Would that be worth it? I only make about $32k a year gross.

Do costs that go toward your deductible but don’t get reimbursed count as qualifying medical expenses?

Also how would it work? Assuming I have a no min balance account, could I just transfer money into it right before I spend it then use the account to pay for the expense? Or do I need to do a consistent contribution and use it if I can?

Thanks!

Edit: typos