WP Multisite – multiple subdomain levels – asking for trouble?

I’m adding a large number of my own domains to a multisite subdomain installation and things seem to be working fine (after a learning curve)

I have a variety of niches and I would like to ‘group’ these sites by niche to make edits/updates easier.

I haven’t found a ‘canned’ solution for that – so wondering what the best method might be

While adding the sites to the network you can’t create multiple levels, ie. niche.site.mainsite.com ; but you can go back and edit the site in the Network Sites list; and it seems to work fine, including accessing the dashboard and the site works live. This way I can just sort the Network Sites list alphabetically, and the group niches are sorted together.

However it is a bit laborious and seems sort of like a hacked solution.

Is there a more elegant way of doing this?

Is there a risk of downstream problems having multiple subdomain levels?