Kindly, if you have time, figure it out by yourself. Below I explain some stuff that might help you to draw your own conclusion.
By the way, I'm a gold tag badge holder here and in Stack Overflow, but I haven't many answers in Super User yet.
A certain overlap across Stack Exchange sites is normal as the definition is at a broader level, not something so specific as Google Sheets formulas.
It's possible to find questions about Google Sheets formulas in (in descending order of the site age):
- Stack Overflow
- Super User
- Web Applications
There might be other sites. You could try the global search at https://stackexchange.com.
Regarding our main site
Most of the users that answer questions about Google Sheets including Google Sheets formulas also answer questions about Google Sheets formulas in Stack Overflow and Super User. You could confirm this by looking at the Top Users page of google-sheets.
As of April 29, 2023, google-sheets is the Web Applications top tag by popularity (determined by the number of questions).
Web Applications is a site about using web applications by end-users. Besides formulas questions about other Google Sheets features, when they are used from an end-user point of view, are allowed.
Regarding tags
Please bear in mind that having tags with the same name in multiple Stack Exchange sites doesn't mean that the tag usage is exactly the same. Each site has its own workings. Some sites might put more attention to the tag wiki than others so the best is to study each site than rely on the tag wiki.
About other SE sites
Stack Overflow is a site for programming questions. In their per-site-meta there are discussions about if spreadsheet formulas are on topic or not. As of April 29, 2023 questions about Google Sheets are allowed and have several users actively answering questions.
Super User is a site for questions about computer software and hardware with certain limitations. Questions about web applications are off-topic, actually, it's fair to say that Web Applications Stack Exchange is a Super User "spin-off" as it was proposed by a Super User moderator at that time and most of the committers to not say that all of them were active Super User users. Questions about Google Sheets formulas are "tolerated" when those questions are about features supported on installable spreadsheets apps like Excel.
Mathematics is a site about Mathematics. If your Google Sheets question requires a strong base in Mathematics probably it might be better suited for this site.
Cross Validated is a site about statistics. If your Google Sheets formula question requires a strong base in Statistics, probably it might be better suited for this site.
Software Engineering is a site for questions about Software Engineering. If your Google Sheets question requires a strong base in Software Engineering probably it might be better suited for this site.
Computer Science Educators is a site for teachers, including "self-teachers". They might help with questions, i.e., to create a plan to learn about stuff that might help self-learners to make the most of Google Sheets formulas. Warning: you might get a lot of arguments about why not to use Google Sheets formulas all the time and get "pushed" to learn about data structures, algorithms, mathematics, etc. Disclaimer: I have barely participated there, but I'm a part-time teacher and over the years I had a lot of interactions with high school, college, and university-level Computer Science teachers.
Stack Exchange has around 180 sites. Most of them are related to Science and Technology. In order to get the best site recommendation, hire me! (just kidding, in the last months I have spent more online-time here than in other places). Seriously, if you need specific guidance about where to ask a question, post a question asking for a site recommendation in Meta Stack Exchange. When doing this, please, please, please, provide practical, detailed questions about problems that you are facing or "a question that you found".
Related
Local
Meta Stack Exchange
- Where can I ask general questions about a multi-platform app?
- Where is the best place to ask question (sic) about Google Spreadsheet
- Build and strengthen the Stack Exchange community with "crossover questions" between sites
Super User Meta
Most recent first.
- Finding hard to fit into right (sic) site between Super User and Web Applications
- How to fix an unfocused post, that I thought was pretty well focused
- Looking for a canonical about troubleshooting issues about using web applications?
Stack Overflow Meta
Most recent first.