I worked as a research tech for a couple of years before going to grad school, to gain more technical skills in the research field that I wanted to pursue. I think the time to clarify what I wanted to do and why I wanted to, were very important. As I interviewed around and met more students in graduate school, I felt that a master degree was also a very valuable option, if you can find a program that offers a masters in the field that you want to specialize in.
I have heard of students who were able to find PIs who funded them for their masters degree. For this route obviously you'll have to make personal connections early on (eventually you have to do this sort of thing anyway). It will be hard getting into a program with a 2.8 GPA with the regular screening method. One way is to make personal connections with admissions somehow e.g. the institute that you already work in? to give you a chance for an interview and perhaps join a mentor/lab directly.
Have you considered a postbac program?
You mentioned maturity - this is very important to elaborate on this in applications, and will definitely work in your favor.
I took a couple of grad school classes while working as a tech, in a way to show that I can pass grad level courses, while working full time. Though, I'm not really sure how much that helped in my applications, in combination with my boss writing in the ref letter that I took the initiative to continue learning on my own.
Whether you're academically ready is completely up to you. For a lot of programs you have classes only for a year, and some programs even say that you shouldn't get A's in all of your classes because it means that you didn't prioritize your research. Do the best that you can in your GREs as an alternative score that you can show with your GPA. Is your science GPA better?
Depending on your work experience background, you can also transition to other science jobs, such as in industry, or go into certificate programs e.g. med tech if you're able to invest in one. You don't have to have an advanced degree to prove to anyone that you're smart.
I hope I answered some of the questions that you had, and good luck!