Extact costum field from log

I have a compicated log that does not follow commun format
......... RType: XXX .......

I want to find an easy way to extract the RType field and the value that corresponds to it XXX (for example).

note that it is not possible to use the KV directive due to complicated format of the log.
I found a solution with string comparison but it is a short lived solution.

Thanks in advance for help

You could probably grok it, but I could not give an example pattern based on the very limited information you have provided.