Dear Miro,
I think I do meistens undetstand your message.
Messner did in solitude manage all logistic on the mountain with resources from only his own personal backpack. Absolute independent and self-contained.

Equipment of various kind in place beforehand from other hands, are reducing the degree of being self contained.

Doing new routes onsight with next to nil information but what is to see and no footsteps nor any equipment, is probably the biggest experience and challenge.

But - having fun and great views are very rewarding too.
Rafael

Was für ein Quatsch! Seit wann sind Zelte Menschen? Auch mit 10 Zelten ist der EINE und EINZIGE Mensch allein und fühlt sich auch meistens einsam. Ich sehe hier eher Plus für die körperliche und mentale Kraft. Ein Minus für Sie!

"Solo" is in solitude on the entire route.

Obvious one can summit alone, with a group of climbers turning lower down.

Reinhold Messner summited Manaslu alone back in 1972.
He soloed Nanga Parbat in 1978 by a new route in alpine style and Everest in 1980, also in alpine style, by a partial new route.
He introduced "Solo" to the Himalayas

No doubt Herman. Buhl did an astonishing achievement going alone from the Silver Saddle to the summit of Nanga Parbat 1953.

So Robert Shauer and Pierre Beghin did strong efforts alone on Makalu.
Kukuczka did actually make use of a allmost snow covered left behind tent, which he dug "free", a minimal minus compared with true solitude.

The UIAA Mountaineering Commission do work with the etichal definitions of style.

All the best!
Rafael Jensen