Can’t you just short the reset pad twice to get into boot mode? If successful, the orange LED will flash (light up?). and a new window will open on the PC. This operation is difficult, so please try several times.
If you still cannot get into boot mode, the XIAO bootloader may be corrupted.
See the link below for instructions on how to repair the bootloader.
‘How to unbrick a dead XIAO using a XIAO(DAPLink) and OpenOCD’