Taking a peek at the web page on Desktop Firefox with its about:memory profiling tool, it says that the game uses about 750MB of memory overall.
Here 222.02MB (WebAssembly.Instance) corresponds to the size of the compiled code (the .wasm file).
Try to see if you can strip the size down by removing any unnecessary packages, setting managed stripping level to high, doing a Release Disk Size optimized build, and removing use of exceptions if possible.
We have had reports that iOS Safari has struggles to load large .wasm files, so that might be a cause. Although it is not completely clear, different versions of iOS Safari have recently had multiple different bugs… (see e.g. iOS 15 + WebGL 2 issue )
The 384.00 MB line above corresponds to the runtime memory usage. That is all the engine code, C# memory, assets that is used. 384 MB does seem a little bit high, but not necessarily too bad. Possibly if you can squeeze the .wasm size to be smaller, then this size will also go down on its own.
(btw the .wasm file was served uncompressed by the server, which can seriously slow down game startup times:
although if the file is being transferred while viewing an ad, then probably the user will not notice)