The last version on which formatting for comments worked was Office 2011 build 14.7.7 (the final update to Office 2011).
Formatting of comments was discontinued in Office 2016. Obviously Ran does not use comments in Excel or he would know this. Ran would save himself and Microsoft embarrassment by not putting BS out as an answer.
The formatting comment issue has come up constantly since Office 2016 came out. Ran is not paying attention.
In the UserVoice forum, Microsoft stated that the existing comment feature is going to be replaced by an entirely new comment feature. How Microsoft will support Type 1 comments in the future is not known. It appears that existing comments will continue to display, and perhaps that will be all.
If you want the ability to format your comments, I suggest using ordinary text boxes or shapes and abandon Comment boxes.
If you want Microsoft to restore the ability to format Type 1 comment boxes, please send feedback to Microsoft using the Smile button in Excel. You're going to have to do a lot of convincing, because Microsoft has already said, "No."
There needs to be a way to change the default formatting for comment boxes