My first prints from my GH5 are a disaster! Where am I going wrong?

I downloaded them and looked at the histograms, and the exposures seem fine. The light tones are up by the right end, so although I agree with earlier advice to Expose to the Right, I don't think these could be exposed much lighter without blowing out some highlights.

The detail and noise levels are mostly OK in these images, except in broad areas. Which raises a question about how they are being sharpened in Lightroom. What is the Masking setting? If it is at 0, it should be raised to 20-50. Masking should keep sharpening within visible edges and not apply it to where it is currently seen in people's skin and on the car and Spitfire surfaces. If surfaces still are too noisy after that, the sharpening level must be lowered.

With respect, I think the Snapseed edit of the Spitfire is not good. It no longer looks natural. On my calibrated monitor, the Snapseed edit is now too blue/green, too light, and lacks black levels. The grass is no longer the color of real grass. The white tent awnings and sky, which were neutral in the original, are now completely out of balance toward green and even more blue.

The original Spitfire still looks better and only needs a few tweaks. In Lightroom I would increase Exposure until the fuselage no longer appears underexposed, if the sky is then blown out I would lower Highlights, if the underside is still too dark I would increase Shadows. But no changes seem to be necessary to the color balance.