Sed Regex String Replacement

I am trying to replace lines containing the word timeout with a specific value using sed. See the example below. Can someone point me to what I am doing wrong here?

There are two types of timeouts, one that is declared as a duration (i.e. with s or m appended ) and one without.

Content in text ($DIR/config.txt) :

timeout="{{key_or_default "/config/timeout" "2s"}}"          # declared as a duration
interval="{{key_or_default "/config/fetchInterval" "5m"}}"
another_timeout="{{key_or_default "/config/timeout" "2"}}"   # declared not as a duration
yet_another_timeout_ms="{{key_or_default "/config/timeout" "2"}}"

Expected outcome

timeout="30s"          # declared as a duration
interval="{{key_or_default "/config/fetchInterval" "5m"}}" # no change needed as it does not have the word timeout
another_timeout="3000"   # declared not as a duration
yet_another_timeout_ms="3000"

sed commands which I tried are below,

# to convert duration-based timeouts to 30s
sed -i 's/"{{.*timeout.*[0-9]+s."/"30s"/' $DIR/config.txt

# to convert non-duration-based timeouts to 3000
sed -i 's/"{{.*timeout.*[0-9]+.}}"/"3000"/' $DIR/config.txt

With duration based:

sed -E -i 's/([a-z_]*timeout\w*=)[^0-9]*([0-9]+[a-z]+)[^0-9]+/\1"30s"/g' $DIR/config.txt

Without duration based:

sed -E -i 's/([a-z_]*timeout\w*=)[^0-9]*([0-9]+")[^0-9]+/\1"3000"/g' $DIR/config.txt

Output:

timeout="30s"
interval="{{key_or_default "/config/fetchInterval" "5m"}}"
another_timeout="3000"
yet_another_timeout_ms="3000"

Using sed

$ sed -Ei.bak 's/\{+[^}]*timeout" "[0-9]+([a-z]*)"}+/3000/' input_file
timeout="3000s"
interval="{{key_or_default "/config/fetchInterval" "5m"}}"
another_timeout="3000"