Find line containing A and then find line containing B and replace ending " by ABC"

[postcd]

Hello,

i am trying to create a bash script that will update file (Thunderbird filtering file) adding new value to the filtering. I will publish the script for anyone to use it so everyone can create global filters for all accounts, but i need help/suggestion regarding following:

Based on following quoted filter file content i think that to adjust one of the sections/filters (for example name="Body contains, delete (ABC)" one, i need to find the line containing "Body contains, delete (ABC)"
and then from this line find first occurrence of "condition=" and on such line replace last character of that line " by a new phrase, for example OR (body,contains,$userinputphrase)"
where $userinputphrase will be supplied by user using for example command: read -r -p "Enter phrase" userinputphrase
and such phrase can be even complicated like: test "phrase2" $';\/ xyz
(while i will need to convert " to \\" but that is another issue i will solve easily i think.)

The filtering file msgFilterRules.dat looks like this for example:

name="Subject contains, delete"
enabled="yes"
type="17"
action="Delete"
condition="OR (subject,contains,spam message) OR (subject,contains,spam2 message)"

name="Sender match, delete"
enabled="yes"
type="1"
action="Delete"
condition="OR (from,is,[email protected]) OR (from,contains,[email protected])"

name="Body contains, delete (ABC)"
enabled="yes"
type="1"
action="Delete"
condition="OR (body,contains,Central Bank of Nigeria) OR (body,contains,test \\"phrase\\" $';\/ abc)"

name="Subject & sender contains, delete"
enabled="yes"
type="1"
action="Delete"
condition="AND (subject,contains,badsubject) AND (from,contains,@baddomain.tld)"

Can you please help with the right sed/awk command?