To my recollection, every piece of Cortex-M firmware I've worked on professionally in the last 5 years has had at least 300K in .text on debug builds, with some going as high as 800K. I wouldn't call anything I've worked on in that time "atypical." Note that these numbers don't include the bootloader - its size isn't relevant here because we're ramloading.

If you're ram-loading encrypted firmware, the code and data have to share RAM. If your firmware is 250K, that leaves you with 270K left. That seems pretty good, but remember that the 2040 and 2350 are dual-core chips. So there's probably a second image you're loading into RAM too. Let's be generous and imagine that the second core is running something relatively small - perhaps a state machine for a timing-sensitive wireless protocol. Maybe that's another 20K of code, and 60K in data. These aren't numbers I pulled out out of my ass, by the way - they're the actual .text and .data regions used by the off-the-shelf Bluetooth firmware that runs on the secondary core of an nRF5340.

So now you're down to 190K in RAM available for your 250K application. I'd call that "normal," not huge at all. And again, this assumes that whatever you're running is smaller than anything I've worked on in years.