I use a Planck or Let’s Split every day, all day, unless I’m at somebody else’s computer. I have a 58-key Preonic with a number row but I mostly ignore it until I’m doing one handed number entry and use the same layouts I do on the smaller boards. I’ve even grown to prefer my game layout on smaller boards over having the number row. It’s all about the layers.
I’m just a tech so my job isn’t exclusively typing but I do use a keyboard a lot for fun as well. I use the nav cluster keys in conjunction with mods all the time for expedited cursor movement and regularly use F-keys and media keys. My base layer arrows and nav cluster are on the same keys in two different layers, it makes it easy to fly the cursor around. I’m not totally happy with my number pad operators placement and still use a Sweet16 for Alt-codes☺because just haven’t written a layer for it but for almost everything else I’m totally happy with 47 keys. This is mostly due to not having to move my hands away from the home row.
One thing I can’t see me adapting well to is missing punctuation that I touch type already like some smaller staggered 40% keyboards have. I even gave up having arrows on the base layer for a while to add back the rest of the missing punctuation. I ended up putting them on a layer and treating it like an island and moving my whole fingers down 1u and over 1u so I know what keys are under my fingers. They are under my Vim arrows so I’m already used to doing that.
My 2¢.