I was interested in this question, live-line work can be done at 220-380 volts. At 10,000 volts, work is only done on a switched-off line. But I read that in other countries people also connect to high-voltage lines to steal electricity. Most likely, in this case, there were no transformers or other connection methods nearby.
11kv is meduim voltage not high, and as I said, it is very common to perform live-line work on medium voltage lines, not sure why is that not done in Russia, have you confirmed that? anyway still, even if the electric company does not approve it, people with the right tools can still do it and it isn't as 'hard' as you may think.
You are right, according to Russian GOSTs, this is medium voltage. For me, this is high

Such lines are used to transmit voltage for 30-40 kilometers from powerful substations to small consumers.
There are no suits that would allow a person to work near such live wires. I admit that there are special mechanized means for work so that a person is at a safe distance, but this is very expensive. Sometimes it is very difficult to get to the place of the breakdown.
That is why, when a breakdown occurs, a team of 3-4 people goes to the site in a UAZ with good cross-country ability and an electrician climbs a pole with a ladder and assembly claws and fixes the fault on the de-energized line.
De-energizing a line for 30-40 km and sending a mobile team is much cheaper than delivering specialized equipment to the same place.

In cities there is enough specialized equipment and electricians, but in remote areas problems are usually fixed in this way. If this is not possible, then other specialists go to the site of the breakdown.
Be sure to share your experience of how electricians in your country fix breakdowns on such lines. I would like to see photos of the equipment.