Yes, the actual representative will never read this and as far as a response goes, you will get an insulting patronizing pre-written letter or just completely ignored. However, some intern or bot should categorize your letter and add it to a report shown to the representative.

By contacting your reps, at the very least, you can be sure that:

You are doing something and exercising one of the tools you've been given to fight this hellscape, which is more than 99%+ of people do.
Your rep will have to ignore even more signs about how much of a piece of shit they are.

I highly recommend contacting your reps as frequently as possible. Resistbot is a great tool that makes writing your reps as easy as sending a text message. There's no need to spend a ton of time writing these letters, they're being categorized, not read. So, you can literally write and send a letter to your reps in less than one minute. I think their Telegram bot costs them less than SMS, so I'd recommend using that.