> Also I've learned about how NW export games load all the layouts into memory and never free any of it
That's not true, layout-by-layout loading frees images when you change layouts, so it only ever has one layout loaded.
This may be true for Construct 2, but the wrappers do NOT behave that way.
NW.js for example has a memory cache nw.exe alongside the main nw.exe, it stores any recently accessed asset into that cache and never lets them go until the entire process is ended (exit game).
This means if the game has 900MB of images/sprites in memory format, that cache will be ~900MB, even on a minimal main title screen layout.
So while you change layout and C2 behaves correctly (dumping the current stuff from memory), Chromium (NW and Chrome) does not. Try it and you will see. Just make a blank layout, throw a lot of 2048 x 2048 single color sprites onto a layout that you never call (Assets Layout) while loading a blank layout at the start. You'll see the processes I am referring to, with one bloated up by however many ~16MB 2048 x 2048 textures you added.
I know Chromium also behave this way on Android Chrome and Crosswalk, so bigger games will eventually eat up a lot of memory on the cache process.
C2 clearing seem to affect GPU VRAM, so layout changes flushes that out correctly, but it doesn't affect the way Chromium handles cache (loading asset from disk to system memory). This is from monitoring GPU vram with Afterburner and different layout transitions. GPU VRAM is behaving correctly but system ram is never released.