I was in a similar situation to yours when it came to video card and RAM (except I have a i7-7700 CPU) and upgrading from 8GB RAM to 16GB made a HUGE difference.
Some months later I installed an SSD as well and now I can run BG3 perfectly fine with custom video settings. I don't turn on all the fancy lighting and shadow effects and keep most other paramenters at medium quality with the exception of models (I hate seeing the blocky hair and beards!).
In general, the upgrade was well worth it even for performing regular pc tasks, not just for gaming
it boots up in an instant!
