Is it really so steep that you can't cross it? I don't recall anything like that, but if you're sure, I believe you ;)
Yes, you can either add embankment=right to a part of the road (but I think it won't be rendered anywhere), or restore the cliff line as an earth bank. You can use https://level0.osmz.ru/ (some documentation: osm.wiki/Level0 ). Log in, enter "way/1307128545.1" into the upper field, then in the large field change "1307128545" to "1307128545.3" (or ".2" or ".4", I can never remember right, but it will tell you if you enter something wrong), change the cliff tag to the earth_bank key and hit "Upload to OSM".

2) I don't argue that a basin shouldn't be mapped with a "natural" key. I only feel that the prefix "disused:" isn't really appropriate for the "natural" key. The prefix "was:" is more encompassing, why not to use it in such cases? But I don't have a hard stance on this issue.

3) "brownfield" is pretty much anything that one was developed, but isn't anymore (and hasn't become totally overgrown as yet). A typical example is a once paved surface with some rubble and some grass or shrubs starting to grow from it, — that is, just what the basin floor are now. After some time, it will become natural=grass, but as yet, it's just a waste of space. And no, there do not need to be any plans for redevelopment for an area to be a brownfield, it's just a present state of land.

1) You misinterpret the "One feature, one OSM element" practice. Its main point is that tags that mean the same should not be duplicated in two OSM entities, and it explicitly states that one OSM entity should only contain tags relating to one processable feature. That's just what I was talking all this time: barrier & the feature enclosed by it should not be mapped as one element, there should be a line for the barrier and a (multi)polygon for the area.
Nothing of the above means that there shouldn't be an entity for the border if there is an entity for the area.
And I definitely insist that a wall should be mapped. We are not constrained by any technical means, so we can map as much info as we can describe. There is no such thing as "responsibility of the person on the ground", and no such thing as inherent "importance" of one thing or other. If something exists, it can freely be mapped ;)) [With possible exceptions for military, personal info etc.]
You can never know how the information from OSM will be used. One can generate maps for sport orienteering using exports from OSM, like this: https://iorient.ru/download/Maps/2023/Spring-in-Jrvezh/map.png
In such cases the difference between walls and slopes is of critical importance.
(to be continued)

Hi! I've reverted some changed to former basins. As I explained at changeset/151908744 , it's better to keep ways and areas separate if each of them can provide some information. So, I restored barrier=retaining_wall to the lines (because you can't cross those lines if you try to walk across); and I restored landuse=brownfield to the areas (because that's what those areas are at present; historic tags are good, but tags that describe present condition are better). Also, I restored was:natural and was:water instead of disused:natural & water, because... uhm... natural objects can't really get disused ;) That prefix is for man-made amenities.

WRT changes, I'll answer at changeset/155785497 .
WRT to invitation: thanks! I visit Armenia only occasionally, and for now it's enough for me to get all the flood from Georgia OSM chat... But I'll definitely bookmark it!

Hi! As stated in the changeset "source" key, it was based on inspection from the ground.
Which basin are you referring to? way/1145130593 ? If yes, then first of all, I separated the outer line & the area: this should always be done when different properties can relate either to the line or to the area. In this case, the line is the wall; and the area (which is best mapped as a multipolygon relation, even though it has only one member) is a brownfield with was:natural=water : relation/17643073 . You can add disused:basin to it, if you wish; I haven't done that just because I didn't think of it.

Yes! That's the correct way of editing information: updating an existing object if you think that it's missing some properties, or changing those properties if they are wrong.
Creating an additional object with those properties only makes an impression that there are two objects in reality, not one. So it's just wrong.
By the way, is this dairy shop also a correction of the already added convenience store, or is it another shop in the same building?
node/12110140269

Hi! Please check carefully if the object you want to add is already there or not. It's the second time you create a duplicate: node/12116925622 vs. node/11293429531 ; node/12112123615 vs. way/1063062536

Is access for pedestrians permitted (as barrier=lift_gate usually implies)? If yes, then it's not access=private, but motor_vehicle=private

reverted in changeset/154249755 : this is the new alignment of the road, based on the gpx tracks (new bridges are still not visible on aerial imagery)

reverted in changeset/154249755 : this is the new alignment of the road, based on the gpx tracks (new bridges are still not visible on aerial imagery)

Hi! Why have you removed name:en tag from nodes 769174152 and 7117622289 ?

Reverted WRT node/10824283609 : most regrettably, it's working, even though it may not seem to be from outside

Hi SleepyAsh! Please don't completely disconnect roads from other roads. I guess you intended only to disconnect the road at the western end? However, you also disconnected it from all other roads that intersected with it. Please pay attention to the yellow and red warnings that the iD editor provides you when editing.
I fixed you edits: changeset/153719183 .

Hi! WRT node/11176460288/history : at the shop entrance the open hours are given as Mo-Su 09:00-22:00

Reverted deletion of node/5439603822 : the board is still there

Why did you remove smoothness=excellent? The asphalt is freshly laid and of good quality. Reverting.

reverted: these road are dead ends, so access=destination is excessive

Florist? Or rather shop=cannabis with cannabis:recreational=no,
cannabis:medical=no,
cannabis:cbd=yes,
cannabis:seeds=yes ?

Hi! Adding generic names, which just state what the nature of the object (like name=Bench on amenity=bench) is discouraged. If an object doesn't have a specific name (for example, "Iakobi's memorial bench"), it should be left without a name tag.