There is "research," and there is "spinning your wheels."  Mind if I ask what secondary or tertiary sources you consulted?  Here's a hint:  If a law was passed in March 2021, it's unlikely you will find much commentary and analysis only six months later.  In fact, even IRS didn't know what it meant until a month or so after some of us pointed out they were reading it incorrectly.  

I have the legislation bookmarked so it took me 10 seconds to download it again and less than a minute to find the section that created the exclusion.  Since it referred to the existing Code Section 85, it took me another 10 seconds to highlight that and click for a Google search on it.  (I just discovered this year that you can do that; I'm not sure it's a new feature, or an old one I hadn't noticed.)  

I could have saved time by just going directly to the Code section.  People are afraid of looking at the law, I suppose because of all the yahoos who complain about how complicated it is.  There are sections that are written in highly technical language for a small audience, but there are other sections that are close to plain English.  Don't avoid the Code but then claim to have done research.  If the Code doesn't answer your question, go to the Regulations if there are any, and then the other IRS pronouncements found on the irs.gov website.  Even IRS publications can be helpful, especially if their contents help your client.  The last resort is a Google search.