How to optimally cluster SA? Relying mainly on services with the “hard” method, or is it still on competitors?

Question

Search Engine Optimization

For example, I used the free coolakov clusterer, choosing a threshold of 3, i.e. clustering, as far as I understood, took place according to the principle of combining requests into a cluster, subject to 3 common URLs in the top 10. For example, here's a cluster:

fire extinguishing designing installation
installation of fire extinguishing moscow
installation maintenance of fire extinguishing
systems installation of fire extinguishing
systems installation of fire extinguishing systems
installation of fire extinguishing systems installation of fire extinguishing
systems moscow
installation of automatic fire extinguishing systems
installation of fire extinguishing

1. As you can see, as a result of clustering, the design got into the cluster with installation. In the case of design and in other similar situations, is it definitely better to place it in another cluster? Or is it worth relying on algorithms and not philosophizing yourself?
2. According to some links of competitors found during the formation of this cluster, the design is missing in the text of the page, despite the fact that the page is located on a request related to the design:

I.e. the phrase can get into the cluster, incl. because the competitor's page is located for this phrase, despite the fact that the phrase itself is not in the semantics of the competitor's page. Is this a common situation and should it be further checked, or can it be neglected?
3. For some competitors who have reached the top, for example, on request, installation of fire extinguishing, on their page there will be about sprinklers, and about gas fire extinguishing, and so on - i.e. they did not bother with clustering and despite this they reached the top - you should not pay attention to this and take it into account, try to follow their path? They may not have a small text of 4000-10000 characters per page, by combining everything into a heap. And it will be more difficult to write the same volume of text exclusively about the installation of fire extinguishing, without writing about water, gas and sprinkler and so on. How to be?

Answer 1

You think correctly, only here are a few nuances, the requests are as niche and low-frequency as possible, I would say zero. Focus on competitors and do not invent. In Yandex, this happens sometimes. I can give a bunch of examples from practice, but there is no time, unfortunately.

Answer 2

You need to be guided by your head and logic
, it’s clear that installation and design are two different things
if you don’t want to think yourself, do it like competitors