Thanks for the detailed breakdown! I'm actually using a mixture of setups depending on the day.
For heavy lifting, I'm on a Windows laptop with a dual-monitor setup that is one screen for my game engine (Godot) and the other for my sprawling Google Docs full of lore. But for editing on the go, I've been relying on an older iPad Air. It's reliable, but honestly, the default Apple Books app is terrible for reading script drafts it constantly reflows my formatting in weird ways and breaks my action lines.
Your mention of EPub Reader Pro handling indentations and keeping the EXT. format intact is a huge selling point for me. I'm currently wrestling with a 200-page visual novel script, and half my editing time is just fighting formatting wars instead of actually fixing dialogue.
I also love that you mentioned syncing between devices. I tend to switch between my iPad and my phone when I'm commuting, so seamless sync is basically a requirement at this point. Does it have cloud sync built-in, or do you manually transfer files?
I might have to give this a shot this weekend. Thanks for sharing your workflow which it's always cool to see how other narrative devs tackle the same headaches!