Lansdscape photography question

I will speak to you as someone who also prefers a lightweight camera and I seldom use my tripod. (I use a small m43 ILC with good IBIS and an assortment of lightweight lenses.) I honestly think you might gain more from working on technique than jumping into a purchase that might not yield the result you're seeking. Looking at the image you posted, it appears to have been shot on quite a windy day. If your shutter speed and handholding technique did not account for that variable, you may have lost sharpness from those factors. I'd suggest you experiment more, making note of your settings, and submit some photos in either your camera forum section, or in the overall critique forum section or both, including your camera settings and lens info, and get some guidance about ways to help you reach your goals with the camera you now own, before you buy another. And before you buy, go to the camera store and hold one if possible, or rent one and see how you like it. Some cameras seem to be our dream camera on paper or on screen but when we handle them, they don't fit our hands or way of shooting. I'd also suggest you explore the gains to be made from editing your images to shape them into what you imagined they'd look like when you shot them.

I do quite a bit of hiking in the Tosco Emilian Apennines, and I have used a LX100, an Olympus EM5 and most recently a Nikon Z7/D810/D850.

I quite like the LX100 and if you really want to go lightweight, then it is still a good choice. You will not see much difference between this camera and M43. When my EM5 was on its last legs and I wanted a replacement for travel and hiking. I considered the EM1 + 12-100 and a Z7 + 24-200. They weigh about the same. I went for the Z7, although a Z5 or Z6 would be a good choice too.

In good light a M43 will do a good job, but a FF sensor will be better for tonal and colour transitions, especially in difficult lighting situations.

You might like this Blog post I made

Put simply, no. 30Mpix is comfortably enough for any reasonable application. More pixels will always improve the definition of your images, anyone who says not has misunderstood.

The practical limits on your IQ will be the lenses and your technique. This latter hinges on knowledge and this basic but reasonable question suggests you could upgrade your knowledge usefully.

Like you I want good IQ and an option of portability. I settled on Fuji. The Sigma is not a bad choice but it is a minority marque (even more than Fuji!) and for outdoors has the disadvantage of no viewfinder. My first digital cameras were like that and difficult to use in bright light.

Finally IBIS is always worth having. I've just gone this way and it is remarkable. Were you to ask my personal suggestion I'd look at the Fuji X-S10.

That is beautiful.

You may wish to read about and consider the Sigma DPx Quattro family of cameras. I am travelling in Hawaii in June and will go equipped with my Sigma DP3Quattro, earlier generation Sigma DP2Merrill, as well as a Canon 5DS. I take primarily landscape and nature photos, hand-held or with monopod. The Sigma cameras produce excellent landscape detail. I have many photos online at Flickr under my name Sandy Fleischmann. You may wish to look at my various albums taken with differing model cameras. I'm currently working through some DPxMerrill photos from our last trip to Hawaii, the cameras love Hawaiian light.

In my 20 years of experience in making prints for sale, the mathematics of the printer's resampling has all been irrelevant. As for captured pixel dimensions divided by target output size, when printing on semigloss or matte paper on my now-retired Epson 4000, I was hard pressed to see any difference in detail between a 300ppi file and a 200ppi file that had been interpolated to 300ppi. Thus, I regard 24" as around the threshold where my a7RIII starts to yield visibly more detail than my GX9.

I’m a huge fan of rocks and stone walls. The good ones are far more stable than any tripod.

I have taken my best landscapes at dawn and twilight. Sometimes handheld, sometimes not. When I want the water to look silky, I use a 10-30 second exposure, so just find a good, dependable rock and you won’t need a tripod. They aren’t as portable but they are very stable.