it didn't seem to suggest that the peripheral clocks would be stopped automatically, hence you may like to try stopping the clocksp73 5.3.4 Stop mode
The Stop mode is based on the Cortex®-M3 deepsleep mode combined with peripheral
clock gating. The voltage regulator can be configured either in normal or low-power mode.
In Stop mode, all clocks in the 1.8 V domain are stopped, the PLL, the HSI and the HSE RC
oscillators are disabled. SRAM and register contents are preserved.
In the Stop mode, all I/O pins keep the same state as in the Run mode.
then there is also the standby mode
hence you may like to try standby mode as wellp75 5.3.5 Standby mode
The Standby mode allows to achieve the lowest power consumption. It is based on the
Cortex®-M3 deepsleep mode, with the voltage regulator disabled. The 1.8 V domain is
consequently powered off. The PLL, the HSI oscillator and the HSE oscillator are also
switched off. SRAM and register contents are lost except for registers in the Backup domain
and Standby circuitry (see Figure 4).
I/O states in Standby mode
In Standby mode, all I/O pins are high impedance except:
• Reset pad (still available)
• TAMPER pin if configured for tamper or calibration out
• WKUP pin, if enabled
oh and use a *real* LiPo LDO that drop out less than < 0.5v if you need that (e.g. running on 4.2v), that 1 Amp ams1117 is apparently not to reduce power more than its cost effectiveness regulating 5v to 3.3v and gives 1 A output reducing complaints about insufficient power. who knows someone may use blue pill to drive their 3d printer hot end
just 2 cents, hope it helps