Hello @senojgnip, and welcome to the forum!
When you have multiple sets of data with the same structure, my advice is to keep all data in a single table, separated by some field, and to use widget linking to allow selecting and working with the different subsets.
This is the approach typically used in databases. For instance, let’s say you are an interior decorator, and for each client you’d like a table of furniture items you’ve picked out for them. Rather than placing them into separate tables (as you might in a traditional spreadsheet), use a single table, add a Client field to it, and create a linked view where you select a Client and see all furniture items connected to that one client. You will still be able to work with that linked table as a regular spreadsheet.
There are several benefits: any improvements you make to the structure (e.g. formulas, column formatting, etc) would apply to all clients without having to manually copy changes. Also it would allow you to summarize data easily across all clients, as well as to create views linked in a different way (e.g. if each item is tied to a supplier, you could create another view to select a supplier and see all items for all clients that come from that supplier).
There are some situations when this advice might not apply – if you have doubts, perhaps you can share more about your use case. But I’d say if you need 20+ of similarly-structured tables, then it’s quite likely that unifying the data is the best approach.