This is what I have tried,

Formula Applicable To Only O365 Beta Channel (Insiders).
• Formula used in cell B1
=TEXTJOIN(", ",,TEXTBEFORE(A1,", ",1),TEXTSPLIT(TEXTAFTER(A1,", ",1),", ")+5)
Or, if you are not using the above Excel Version, but using either Excel 2019, 2021 or Regular O365, then,

• Formula used in cell B1
=TEXTJOIN(", ",,LEFT(A1,FIND(",",A1)-1),IFERROR(
FILTERXML("<a><b>"&SUBSTITUTE(A1,", ","</b><b>")&"</b></a>","//b")+5,""))
Edit
One improvised approach:
=TEXTJOIN(", ",,TEXTBEFORE(A1,", ",1),IFERROR(TEXTSPLIT(A1,", ")+5,""))
You can also accomplish this task quite easily with Power Query.