> B.J. is an Elected Head of state.
Just so we're using the same terms, here, I think it is conventional to describe Johnson's role as "head of government".[0]
> members of the Cabinet - those that enact legislation - are unelected.
The Commissioners are appointed by the heads of government of the member states, exactly the process you suggested in your earlier comment. If you think that Boris would be limited to picking ministers who had actually gone to the trouble of winning an election, then you'll be surprised to read about the 19 unelected ministers that Boris has chosen.[1]
> Ursula Von Der Leyen did not stand for election.
While Boris did manage to win 25,351 votes in his constituency, and 92,153 in his leadership election, there is nothing preventing a UK prime minister from gaining power through a backroom deal, such as Theresa May's unopposed leadership "election" in 2016, or Brown taking over from Blair in 2007.
This is of course accepted since the PM must hold the confidence of the parliament, but the same is true of the Commission President, who must receive the approval of an absolute majority of MEPs.[2] In fact she (together with her Commission) was elected with 461 votes to 157.[3]
> She was imposed [on] EU voters, probably less than 2% of whom had even heard of her.
I agree that this is a failing of the process and the political culture of the EU.
> EU elections have very low rates of participation, EU voters have very low awareness of any of the material issues
That could be interpreted as meaning that a large proportion of EU citizens don't feel particularly affected by the EU's decisions, which would mean that the EU is (correctly) leaving national issues to national politicians (who then influence the decisions of the Commission through their appointed commissioner).
> MEPs have very little ability to influence legislation
Any influence the MEPs lack just means more power to the national governments who control their respective commissioners. I don't see how this process is any worse than having an unelected House of Lords which contains hereditary peers.
> and very limited ability to censure leaders.
MEPs have the power to call a Vote Of No Confidence in a Commission, which can lead to its dismissal. This came close to happening in 1997 during the BSE crisis.[4]
> So yes, Boris Johnson (and Macron, and Merkel) have considerably more legitimacy than any members of the EU apparatus
If by "any members of the EU apparatus" you mean "specifically Ursula Von Der Leyen" then you almost have a point. I would also be more convinced if you had limited the first part of your statement to just Merkel, as I believe that Germany's electoral system is more proportional than the UK's and doesn't have the "safe seats" problem of FPTP. (The two-rounds system that Macron was elected under has its own problems).
As a thought experiment, imagine that Biden had won the presidency with just 44% of the popular vote, and that win also granted him an effective super-majority in both houses of Congress (since the UK only requires a simple majority to force through constitutional changes). I can only imagine that scenario leading to civil war in the US, and yet this equivalent situation in the UK lets some people think they can throw stones at the EU's democratic character.
[0] https://en.wikipedia.org/wiki/List_of_current_heads_of_state...
[1] https://bylinetimes.com/2021/02/19/brexit-revives-the-power-...
[2] https://www.europarl.europa.eu/news/en/faq/8/how-are-the-com...
[3] https://www.europarl.europa.eu/news/en/press-room/20191121IP...
[4] https://www.politico.eu/article/meps-split-over-vote-of-no-c...