I can't seem to find any release notes that says V13.2.6.0.TLCCNXM is based on Android 13. Changelog just shows General optimaization, fixes and latest translation updates. Therefore, I would assume its still based on Android 12.
Any reason that the latest firmware for X12 is fastboot rather than recovery? Since recovery rom has been supported by skkk twrp for sometime now.
xiaomi.eu_multi_XM12_V13.2.6.0.TLCCNXM_v13-13-fastboot.zip