Thanks - that’s OK.
If using Arduino framework the ‘escape hatch’ button C0 is built in. For Simplicity Studio development you need to create that yourself.
Removing HFXO is not necessary for Zigbee SED (Sleepy End Device). The stack handles that.
As mentioned Sleep (EM2) should be about 5uA on the 'MG24 but on the XIAO MG24 it’s about 40uA - that is for non-Arduino development.
Deep Sleep (EM4) is not used in Silabs Zigbee development.