If you want to make a bicycle-pedestrian path, then I'd recommend adding all the tags I've mentioned in the second list. highway=path without other tags is often interpreted as an unpaved forest path. By adding designated access and surface, routers would know that this is convenient and obstacle-free path both for pedestrians and cyclists.

If there are some places where it's not really designated for bicycles, but a person may often choose it due to being more safe than carriageway, then use highway=footway and add bicycle=yes in these places.

Apparently, not all of these playgrounds are actually public. Please actually survey before answering StreetComplete questions

changeset/145592619

If it's signed and it's not just a "private land" sign, but explicit ban on other people being there, then ok.

The only sign I see on aerials is a sign near the playground and at the time you see it, you are already there.

https://fotoladu.maaamet.ee/etak.php?B=59.43295290801652&L=24.80795025799743&fotoladu

I think it's more important to change playground's access, as it's currently explicitly public.

Hi, what exactly is preventing access here?

There is also an outpost, but it looks like many dislike this tag. Maybe this will be accepted in future osm.wiki/Proposal:Pickup_points

Hi,
supermarket is a place you can enter and shop. Maybe this should be a dark_store=*

Also, do you know if it should be pickup=yes or no?

Hi, you should use
highway=footway
footway=sidewalk

for pedestrian only sidewalk or

highway=path
bicycle=designated
foot=designated
footway=sidewalk
surface**=*

for a combined bicycle-pedestrian one

Hi, you've added name to the building, but the data doesn't say what it's used for. I recommend adding

Check OSM wiki
and see if these tags are applicable or maybe something else
osm.wiki

industrial=warehouse
office=construction_company
craft=roofer
building=warehouse

You can add tags at the bottom section when you select the building

Please keep your changesets local next time and upload each country separately, thank you.

Thanks for a thorough answer.
I recommend to remove name, description and website from the building and add add office=research or office=company for the node.

You can do this at the bottom section "Tags" when you select the node or the building.

You can also move the node closer to one of the staircase entrances or whatever entrance you are using. Just don't put it too close to the edge or those maps which want to display it, may have not room for the text.

Hi, please use name in a local language as a default name

Hi, features should only be added once. Currently it's added both as a node and on the building.

This looks like an apartment block, I assume people live there and they are not part of GoGoNano. So you should remove the tags added to the building.

Nothing describes what it is except description text. I recommend adding office=research or office=company

Is this just a legal address, or does GoGoNano really function there?

It's called block heater
https://en.wikipedia.org/wiki/Block_heater

I don't know anything about them, but see if

socket socket:*=*

or power outlet
power=outlet

are applicable

Hi, do Germans still use "Kreis Harrien" name? Harju kreis is a historical name, but Harjumaa borders don't event match with it. I'd remove it.

Hi, is the screen reachable from a wheelchair? What about top shelves?

Hi, uturn restriction should probably also be removed. Nothing prevents it I think.

I've changed all mentioned parking lots to public access. Haven't seen any signs which would make them non-public. Be careful next time!

While multipolygon can be used to represent areas with holes using inner and outer members, a multipolygon can represent multiple disjointed areas by having only outer members. It's better supported by data consumers than a site relation, so I think we should use it where we can.

Site has an advantage when you need a relation having not only areas, but for example a node and an area, which is not the case here.

I think it's better to use multipolygon relation as it's better supported

And for the airport's address you've put a Russian street name. We don't really translate addresses even if it was in a correct tag. I'll revert this changeset.