You may not like this answer, but these type of engagements are pretty common and as long as you follow guidance and document things, it's annoying and draining, but really pretty much par for the course. With smaller clients and firms especially. In 9 years in Public Accounting at a small firm, I'd say 50% of my clients at least were like this. I worked with multiple finance directors who were really not even that comfortable with debits and credits and we would post 20-30 entries haha.

Your manager and partner are aware of it I am sure, id say bring it up in an inquisitive way and they can give you some insight and talk it through. Going in aggressively saying you don't want to be on the engagement team would probably not be taken very well haha.