RegExp in Zapier not returning any values

I'm trying to extract some values from discord message in Zapier. The content of the message should look somewhat like this (almost like YAML):

channel: <#1234567890123456789>
as: Bot nicname
image: http://example.com/
content:
Hello, world!

Where image and as fields are optional.

I have created 2 regular expressions to fulfill this task:

Python:

import re
r = re.compile(r"(?:channel:)? ?<#(?P<channel>\d+)>\n+(?:as: ?(?P<as>.+)\n+)?(:?image: ?(?P<image>.+)\n+)?content:\n*(?P<content>[\s\S]+)")

JS:

let r = /(?:channel:)? ?<#(?<channel>\d+)>\n+(?:as: ?(?<as>.+)\n+)?(?:image: ?(?<image>.+)\n+)?content:\n*(?<content>[\s\S]+)/;

What I tried:

Testing regexes in regexr and pythex. Both work fine for me.

Then I entered them into Zapier:

• In the Text->Formatter by Zapier->Extract pattern - returns _matched: false
• In the Run Python field

output from the python code:

    groups: null
    id: <ID>
    runtime_meta:
    memory_used_mb: 57
    duration_ms: 3
    logs:
    1. re.compile('(?:channel:)? ?<#(?P<channel>\\d+)>\\n+(?:as: ?(?P<nick>.+)\\n+)?(:?image: ?(?P<image>.+)\\n+)?content:\\n*(?P<content>[\\s\\S]+)')
    2. 'channel: <#1234567890123456> \nas: bot nickname\ncontent:\nHello, world!'
    3. None

(and later in the Run JavaScript with similar result)

What works (somewhat):

When trying to debug it i removed image part of the regexp (in the Text->Extract expression):

(?:channel:)? ?<#(?P<channel>\d+)>\n+(?:as: ?(?P<as>.+)\n+)?content:\n*(?P<content>[\s\S]+)

With the input:

channel: <#1234567890123456>
as: INFO
content:
Hello, world!

And the result was as expected:

output:
0: 1234567890123456
1: INFO
2: Hello, world!
_end: 68
_matched: true
_start: 0
as: INFO
channel: 1234567890123456
content: Hello, world!

---

Any help with getting it to work is appreciated :)