In some ways embedded is easier, in others much harder. Doing it all on your own is hard, but if you have a good team backing you I think it is actually easier than trying to write a large desktop app in native.

No OS to get in your way. No decades of legacy APIs to clog things up. Because the entire world is understandable, no need to be concerned about someone else's thread ruining your day.

All your I/O channels are well measured and have know latency and throughput. If you are lucky enough enough to work with SRAM, then you even get a nice constant access speed to memory.

Interrupt routines are a fancy way to say "callback" and Direct Memory Access is a nice way to say "memcopy without CPU overhead".

That said, the initial getting up and running part is hard, that is why lots of pre-existing systems with their own little runtime exist.