When I find the time and I need a background I found nowhere, I play with
Flowscape to do something. It has fog, and not a static one but a true moving one! Even some dead branches or stones can be placed naturally on the slides.
The only limitation I find to that program is we have to use a squared ground and model from.
I never tried to do that, because I certainly not have an enough powerful comp. But the importation of figures, or any object, is possible in Flowscape.
With Flowscape, no render time. You make your scene, and you click like for a camera to take a photo.
But Agent is right about Bryce (where I was always so bad to do forests

even with the 2D part), it's a good program.
And you never used Carrara Agent, but you wonder why Daz stopped to develop Bryce? I always assumed it was to sell their Carrara.
Llola, it's perhaps possible for your to see how a scene in Bryce is built thanks to a freebie. It's a sea cave, that you can find on Deviantart or on Rendo.
https://www.thefantasiesattic.net/attic/index.php?topic=12660.0From what I remember, the creator made it starting from box. When I discovered it, I played with and put scenes in the FA gallery; we had to remove images on several years with the new host, so it's no longer online, and I can't move because of a cat in my lap to reach the flash drive

If I'm able to find again a site with Wings3d tutos, I'll be back to add the link on PFD. I think it was a French site, but I can still help to translate in special topics. There were easy tutos, like how making a simple dice, or a barrel.
Like I said another time, we have tutos on FA
https://www.thefantasiesattic.net/attic/index.php?board=61.0 but those with attached files have lost their files. Yet to start well in Wings3D I followed a series of videos to create some 'dock'