About the example question
With due respect, the question OP should review how they are making expectations about "mobile apps". Not because Google and Microsoft have similar apps, it means that both have the same features.
Personally I think that Stack Exchange (SE), as a default policy, should require users asking about software applications to throughly study the app help / resources for end-users before asking a question, specially if they are "beginners" (as app users, not as SE users) / not app power users and in questions asking "how to do X with Y" as most of these questions are poor worded questions that is not clear if they should be sent direclty to the app developers as feedback, as a feature request, as a customer service ticket instead of posting them in SE sites or if they are a XY problem.
I'm OK if there are sites that allow "beginner" questions but that treated as an exception to the SE model and as such should be clearly specified, probably in the tour, /help/on-topic
and in the /help/how-to-ask
pages from the respective site help center, at least to point users to the respective per-site meta.
Question migration
Don't migrate the sample question again until it's clarified if it's a good fit for a destination site. As a moderator, you might try to contact the moderators of the possible destination sites in Teacher Lounge chatroom. Ref. What is migration and how does it work?
Change of Super User scope
I don't think that Super User should change its scope, but it's true that there are some topics that might not have being very clearly specified if there is a SE site for them, like questions that are platform independent, i.e. "What is a Discord server", "What is a Slack channel". There is an old initiative (from 2013) in Meta Stack Exchange related to this: Build and strengthen the Stack Exchange community with "crossover questions" between sites. As of April 16, 2023 it has status-deferred.
P.S. Platform independent questions related to customer service and other stuff that can only be answered by official service agents are off-topic in SE.
The term "cross-platform mobile apps" doesn't look to be appropiate as a question title, it might be "cross-platform software" or something alike.
From Telegram (software) | Wikipedia (links not included):
Telegram Messenger is a globally accessible freemium, cross-platform, encrypted, cloud-based and centralized instant messaging (IM) service.
Related
Super User Meta
Meta Stack Exchange
- What is the right site to ask about Foursquare app from 2012
- Where can I ask questions about mobile app in SE sites? from 2012
- On which Stackexchange website should I ask about mobile applications? from 2014
- Where is the best place to ask questions about Google Spreadsheet? from 2014
- Is there a Stack Exchange site for asking questions about Google apps? from 2015
- Where can I ask questions regarding apps? from 2017