I've been down this road a few times with mobile-only visual novels, so here's the real talk: you can often play 'Mystic Messenger' on a PC without using traditional emulators like BlueStacks, but the method depends on what platform you're on and what you mean by "without an emulator."
On Windows 11, Microsoft added Windows Subsystem for Android (WSA), which lets you run Android apps from the Amazon Appstore or sideload APKs. It's not the same as a third-party emulator — it feels more integrated — and I managed to run chat-based apps this way. On Macs with M1/M2 chips, some iPhone apps are available directly in the Mac App Store if the developer allows it, so you might be able to install 'Mystic Messenger' that way.
Heads-up: the game relies on timed notifications and event scheduling, so even when it runs on PC via WSA or as an iOS app on a Mac, you may need to fiddle with permissions, time settings, and notification permissions. Also be careful if you sideload APKs — grab files from reputable sources and back up saves if possible. Check Cheritz's official channels for any native PC release and try the least invasive method first — I usually test with a free route before signing in with my main account.