I know you've probably had a look at it and decided it wasn't worth it, but could it be possible to generate a LUA script on the client side and EVAL it once it's completely generated ?
You'd need to periodically SCRIPT FLUSH to not let old scripts linger
I think it can be done through LUA, or even just by using "MULTI" command but I would still have to handle asynchronous replies on the client-side where it would get hairy regardless.
In any case I'm fairly certain there are multiple ways to solve such problems, normally I wouldn't even bother writing an in-house database client library but RESP is so amazing and simple that it doesn't take much time build a client library for Redis.
You'd need to periodically SCRIPT FLUSH to not let old scripts linger