Regex for field extraction with or without comma

[magriii]

I found that the format of a sourcetype had changed some time ago.
Now I need to extract the data correctly for both cases.

2022-01-11 17:40:59.000, SEVERITY="123", DESCRIPTION="ooops"
2018-01-24 16:35:05 SEVERITY="112", DESCRIPTION="blabla"

Extraction for the first type of entries works with this regex that was build with splunk field extraction

^(?P<dt>[^,]+)[^"\n]*"(?P<SEVERITY>\d+)[^=\n]*="(?P<DESCRIPTION>[^"]+)

How can the regex be expanded to split either at "," or at the second space, if the comma is missing?

An idea is to capture always at the second space and remove the comma or split before SEVERITY and remove the comma. I didn't get either working.

You can find the regex at https://regex101.com/r/mxdAyx/1 

Thanks

[ITWhisperer]

^(?P<dt>[^ ]+ [^ ,]+)[^"\n]*"(?P<SEVERITY>\d+)[^=\n]*="(?P<DESCRIPTION>[^"]+)