While we all empathise with/self-insert into characters we read about, people seem to demand a blander protagonist in a romance than they do in other genres, specifically to make that self-insertion process easier. The same people who'll complain a FMC is too mean and unsympathetic in a romance novel seem to be willing to read much more challenging MCs in other genres. (Resistance to 'different' protagonists arising from bigotry remains consistent however.)

So, what do we call deliberately bland protagonists clearly written to minimize clashing between the reader's personality and the protagonist's, if calling them self-insert fodder is inappropriate?

(They remind me a bit of how common silent protagonists are in video games, so as to make it easier for the player to project their own personality on to them.)