With an iPhone, when you click on an input field, the on-screen keyboard pops up, and you can type right away.
On an android (latest samsung flagship), the keyboard shows up but is frozen for a second before you can type.
I feel this and I’m guessing iOS is a lot more closer to the hardware, while android runs on top of Java, so there is more to process. Maybe its just me.
The keyboard pops up, but is not responsive right away. This very thing happened today on my work phone (which has a bunch of MS defender/enterprise policies and apps managed by the company, forced background app updates etc, which could explain this) but I recall it also being a regular thing with all Samsung flagships I've had over the years. It's the feeling of a very slight delay (it could be a matter of as low as 200 ms) for important components which are operating-system controlled, such as the on-screen keyboard. It feels laggy, as if an app or a background process impacts the responsiveness of low level OS features.
On iOS, this was never something I had to experience. Slow apps are killed, iOS is brutal in this regard, but it protects the core OS-level components such as the keyboard. Try it out, load a few apps and try switching between them, where one of them had the keyboard uplled up. This is something regular users will likely never feel, but if you've been around since amiga 500, you'll definitelly feel it.
This must be a glitch particular to Samsung phones. I use flagship Google Pixel phones and have NEVER witnessed such a lag. I tap on an input field with my left thumb, immediately the keyboard shows up, and I immediately smash any letter with my right thumb and it does register it. So, blame Samsung, not Android.
I am not too surprised though. Samsung has a reputation for bloating their Android stack with junk.