Every state has a Parent Training and Information Center. This is the one for TN: https://www.familyvoicestn.org/resources/education/ This site also says they are the only Parent Training and Information Center in TN: https://tnstep.info/ (Not sure which is the right group - there should only be one.)
In my area (I'm in PA), The Arc has advocates that can help with IEPs. TN's Arc might be able to help: https://familyengagementtn.com/
From my experience, when content is modified, the student is taken off a 'diploma track' and put on a 'certificate of completion' track. This has more info: https://adayinourshoes.com/iep-accommodations-modifications/
I don't know if WC is a magnet for issues, I think a lot of it is size bias-- WC and Downingtown both have 10-12000 students, so it feels more frequent.
Anyway, I need to come up with a list for parents to use to ask questions when hiring an advocate. There are a few on that list who I would not recommend.... and in fact I would recommend not reaching out to them.
but in this litigious society, I'm certainly not going to say who or why.