My experience with AA was different, probably because it involved a LCC in Europe.

AA ORD-FRA was delayed by 2 hours. As a result I missed my Ryan air flight to FRL (BLQ). AA denied any responsibility and said because it was a separate ticket there was nothing they can or should do for me.

I would hope your experience would be difference due to OW.

First of all, is this a nesting ticket? I presume you are flying back the same routing.
Are there other AA flights after yours?
What would you like AA to do for you? Most likely it will be a BA solution, not an AA solution.
Keep in mind that if you miss your AA flight and do not call, their policy is to cancel all segments. If you get a nasty GA, you will have some troubles getting this reinstated. You will be able to do it, but just be aware of that potential pitfall as well.

Good Luck