Extract Text from Status Summary field

[FilAra]

I want to extract specific parts of text from the Status Summary field.

Currently my team uses this text field to provide information about the issue.

We use this text structure in the Status Summary Field to inform management about the issue: 

RAG @[color]

PTG: [text]
[text]

REASON: [text]
[text]

I want to create a column in our structure to show only and exclusively PTG information with all the text after "PTG:" and before "REASON:", whether RAG @Amber or RAG @red.

I have tried several solutions presented here in the community (regex, substringafter,..) and other websites but the JIRA version we use in our company does not have many of these formulas available or I'm not using correctly...
Is there any solution using simplified formulas?
Thanks in advance!