Buy a copy of "The Family of Man" from The Museum of Modern Art. Buy a book of landscape images by Ansel Adams. Don't just "look at the photos" - study them. See how they're lit. See how they're composed. See how the portraits are posed and lit. Think about how you might recreate them.
For landscapes, see what time of day they've been shot. How they were composed, with sensitivity to foreground, middle ground, background.
Go to Flickr and check out the Flickr group for A7II:
https://www.flickr.com/groups/a7m2/pool/with/25084142317/
Check out a creative landscape photographer with a rather common camera like the Nikon D5100 - I just randomly picked
https://www.flickr.com/photos/107485243@N04/with/23499461179/ Study her photos. See how she gets spectacular images with a camera MUCH less sophisticated than an A7II.
Study. Then go shooting - take your A7II to an interesting new place with the money you would spend on an A7RIII. You'll get vastly better images without buying a new camera.
Mordi