For example, if I wanted to always see rows 5, 10 and 15, as far as I can tell, I would have to freeze every row from 1 to 15. But is it possible to only freeze the specified rows so that if I scrolled down, the first four rows could be 5, 10, 15 and 20.
I doubt it.
I don’t know exactly why you want that, but it seems like it should be solvable in other ways.
Let’s say you have some definitions in rows 1-15 and a table of data from 16-onwards where you’d like to see row 5,10&15 while you scroll down. In that case I’d move the definitions to a separate sheet. In the data sheet I’d use rows 1-3 to refer to the fields in rows 5,10&15 in the definition sheet and freeze (or use a table) after row 3.
If it needs to be even more dynamic than that example, say you want to change exactly what lines are visible on the fly, I’d put everything in a table or filter and add a column labeled “visible” and use that to filter the visible rows by Yes/No or whatever type of selection choice you put there. I use this approach a lot to convert data and calculations spanning several rows into one line csv exports. F.i. having a row called “export filter” I can easily filter to the lines that I need to export.
I’m not gonna lie, I mostly just use Calc as a dynamic text editor, so I have no idea what a lot of that means but I think I’m just going to move some of the rows to a separate sheet. I think this would be the best solution because it would do something similar to what it want, it just for some reason didn’t cross my mind until I read your comment.