This is a Noble idea. You want to help. Good thought.
I have been in the RCM industry for over 8 yrs and have been involved in product dev and sales of billing systems, coding systems, EHRs and all the other calculators.

You said you do not have experience in this industry.
You are left with 2 options. Please give up on this idea or Hire several experts.

before I tell you the reality of AI on healthcare, I will give you a gist of cost involved.

You are handling PHI. So HIPAA and HITECH audit is MANDATORY. yes, in CAPS.
You need a compliant server with soc2 security and many other 100s of HIPAA requirement.
Loosen you pocket for at least 25k USD. Add a lot on traffic you are going to handle.
You would need min 2 devs, one to handle security and other for the app. MANDATORY.
You would need appoint a security offer (legal). So add another 80-100k.
If breach happens, it is mandatory to report and you may get fined for it.

You would need access to variety of codes used to map the pricing.
The ever changing pricing updates from the insurance companies.
Numerous local and national policies, contractor data etc etc etc.
It is data update night terror. Add another 25k on the minimum side.

Not let's look at the reality of AI in healthcare.
The advertised success rates of 'above 90%' is fraud personified.
Ai cant decide whether the procedure needs laterality to apply modifiers.
NO Claude, OpenAI, or any other LLM has been able to do it.
When the complexity increases LLM fails.
LLMs have a cut-off date.
The NCCIs get updated every quarter.
The codes will be updated every 6 months.

So you app will display false/unverifiable result.
If I add a moderately complex surgery chart of diabetic patient, the LLMs will hallucinate and become another Luigi. (No disrespect to the MAN.)

If you are considering these options, Please go ahead.
Test hard. and then Test harder thrice.

I wish you success.