find some word in text list file and a bit change to them

[RolanRoll]

hi
I need to find some word in my text list file for example V_20220412 in
S1A_IW_SLC__1SDV_20220412T022912_20220412T022940_042734_05197D_3860

then i want to omit " _" so then , it is like this: V20220412
and then i want to get one day before this date : V20220411
after doing these steps for all rows in text list file ,I want to save them in another text file like this:
V20220411
V20220318
V20220222
V20220128
V20220105