Hello,
1/ Grid Calculator Pro Edition
I use this plugin for Adobe Indesign : Grid Calculator Pro Edition. I think it would be interesting to integrate the same kind of tool under Affinity Publisher.
This makes it possible to calculate the columns precisely or to have a baseline with the perfect rhythm. It is also possible to apply different rhythms depending on the size of the typography (because of course, in the same document there are different sizes of typography). Here are some explanatory videos : https://www.designersbookshop.com/grid-calculator-pro-edition-videos.html
By default Indesign does not offer all these features... at least it is much less pushed. I think such a tool would be a good thing for Affinity Publisher.
2/ Typographic scale
I think it would also be useful to add a tool to calculate a typographic scale : https://www.layoutgridcalculator.com/typographic-scale
3/ Guides manager
Moreover in the guides manager, when you want a grid, you need to define the number of columns. The worry is that it is impossible to know the exact width of a column and a total width of all columns and all gutters. We need to close the tool to manually measure the width and get information. I think it would be useful to specify the size (width) of a column that the tool generates... or even give the possibility to edit the width. Last, when adding lines, the space between the lines is exactly the same as the space between the columns. It would be interesting to have a different space between rows and columns... and also to be able to have and / or edit this value (the width of the gutters).
What do you think ?