yes it exist :
there is an existing Android 13 based stock firmware for your device
https://www.asus.com/mobile-handhelds/phones/zenfone/zenfone-8/helpdesk_bios?model2Name=Zenfone-8
But /e/OS-T builds are expected to include the needed firmware parts.
$ ./payload-dumper-go -o OutputFolder -p dtbo,vbmeta,recovery e-2.1-t-20240605406922-dev-sake.zip
Found partitions:
abl (602 kB), aop (246 kB), bluetooth (1.1 MB), boot (101 MB), cpucp (106 kB), devcfg (49 kB), dsp (67 MB), dtbo (25 MB), featenabler (90 kB), hyp (3.7 MB), keymaster (287 kB), modem (182 MB), multiimgoem (16 kB), odm (1.5 MB), product (629 MB), qupfw (57 kB), qweslicstore (262 kB), shrm (49 kB), system (1.4 GB), system_ext (359 MB), tz (3.8 MB), uefisecapp (127 kB), vbmeta (8.2 kB), vbmeta_system (4.1 kB), vendor (1.0 GB), vendor_boot (101 MB), vendor_dlkm (36 MB), xbl (3.7 MB), xbl_config (221 kB), xrom (537 MB)
in conclusion, you should be abble to dirty-flash “e-2.1-t” over “e-1.19-s” via recovery without dataloss
Go direct to point (8) or (9) of this guide :