Hey, I'm super happy that WriteRush is helping you with your writing projects, and I hope WriteRush can keep helping you with your writing journey!
For your first suggestion, I'll probably add a togglable button that will make the chapter sidebar stay open. That would likely be helpful for many people.
For your second suggestion, I'll definitely add more typing sounds. That's been on my to-do list for a while, but I've been procrastinating it lol. I don't think custom sounds would work (because of how indexedDB functions), but I'll see if I can do it anyway. The sounds in WriteRush currently aren't that good, so I'll probably update those. If you have typing sound suggestions (or any suggestions in general), tell me and I'll add them!
Thanks so much, and have fun using WriteRush!