Sorry, but floats for layout at this point in time? That just over complicates everything. If you don't want to use grid, use flexbox.
Also, your points on grid are not accurate. In a custom site, all your code would be used. You can adapt the sizes of each grid column, and even then, you can fit grid content into multiple columns or rows. It is very flexible.
Changing the number of columns is possible. Even then, you can make it so items can span multiple columns so you can have different visual column designs without adding a new container (ie. A 12 column can be 1, 2, 3, 4, 6, 7, 12 columns just from where you assign item).
Sorry, but floats for layout at this point in time? That just over complicates everything. If you don't want to use grid, use flexbox.
Also, your points on grid are not accurate. In a custom site, all your code would be used. You can adapt the sizes of each grid column, and even then, you can fit grid content into multiple columns or rows. It is very flexible.
Changing the number of columns is possible. Even then, you can make it so items can span multiple columns so you can have different visual column designs without adding a new container (ie. A 12 column can be 1, 2, 3, 4, 6, 7, 12 columns just from where you assign item).
I suggest you look into it some more.
css-tricks.com/snippets/css/comple...
developer.mozilla.org/en-US/docs/L...
developer.mozilla.org/en-US/docs/W...
learncssgrid.com/