As reported on Discord, there is a bug in drivers/serial/uart_nrfx_uarte.c that leads to failing compilation:
zephyr/drivers/serial/uart_nrfx_uarte.c: In function 'cbwt_uarte_async_init':
zephyr/drivers/serial/uart_nrfx_uarte.c:1578:37: error: unused variable 'cbwt_data' [-Werror=unused-variable]
1578 | struct uarte_async_rx_cbwt *cbwt_data = cfg->cbwt_data;
| ^~~~~~~~~
cc1.exe: all warnings being treated as errors
ninja: build stopped: subcommand failed.
This is fixed in the (now merged) PR https://github.com/zephyrproject-rtos/zephyr/pull/106566. However NCS 3.3.0-rc2 does not include this commit.