Is an upgrade from Lumix G3 viable for a noob photograhper?

Dear friend, upgrade could be considered in 2 aspects.

Upgrade the body is looking for a better sensor (better high ISO images, better DR) and better features + better video. Without doubt it would be replaced again few years later when higher pixel comes, better sensor invented + more new features.

Lens would be a much longer term investment as long as you stay in the same system. UWA? Fast Prime? Telephoto? Tiny kit 12-32 + 35-100 or pro f/2.8 zooms...?

Comparing G3 to the modern day bodies (not in position to comment on Oly product) GX7/G7, GM1/GM5, you could expect to see a quite obvious improvement in terms of sharpness and ISO performance. For my experience, my G1 could go max ISO400, GF3 max at ISO800 and usable at USO1600, GX7 is good at ISO3200, usable at ISO6400. G7 could expect a bit better. As GMs and G7 share the same sensor and likely similar CPU of GX7 (G7 is newer), I expect it might be at least the same if not better. The upgrade is positive. In terms of G5/G6, the difference to G3 might be less obvious. You might have also missed a lot of new features that has been developed in the last few years after G3.

I originally also preferred dslr-like body. But after settling down with the ranger finder style GF, GXs, I now have no problem in handling them.

I would upgrade G3, specially GX7/G6 is so cheap now. In longer term, I would keep on improve my lens portfolio...