how much benefit is there of working as a predoctoral research assistant I would like to do a PhD in a machine learning related topic and want to enhance my resume. I am considering looking for roles as volunteer research assistant and was wondering whether the experience would be beneficial if I do manage to find one. From what I've read online a lot of what predoctoral research assistants do involve menial tasks (cleaning up data) and wasn't sure if this would strengthen my application.
I'd hope to look for a research role in an area directly related to my interest. But an alternative I was considering was to just work at a job which may not have a direct connection to my interests but is slightly more financially beneficial.
I was hoping to get some advice on what would be better
In many circumstances, yes, predoctoral research experience is an asset, in particular if you can get a strong letter of support for your graduate application, and can contribute to some publications.
Financial aspects are a consideration also, but it's hard to judge given the available information in the question.