Her performance was entertaining, the vocals were well off but it just sounded like any other artist in their 60s trying to sing a song that's nearly 30 years old followed by a nowhere near as good recent offering, every artist or band comes to this point. Nobody can perform like they are 25 forever, social media in particular seems shocked she isn't immortal or something, her music and live performances are for the fans not the haters.
I think BBC Radio 6 Music DJs (& music writers) Mark Radcliffe & Stuart Maconie summed things up well. Basically saying it is somewhat ironic that she is the only surviving member of the 1980s pop icons (Michael Jackson; Prince; George Michael; Whitney Houston all RIP, although for the first RIH might be more apt) to still be alive; and yet for well over the past decade when she performs or releases new material you half wish that she had retired as she is harming her legacy.
I also agreed with them that her reputation within the music industry over the decades has meant that she has created a lot of people within it who whilst they admire her; they don't like her. Hence, misfires are picked up on.
Whether thinking about her diva antics from when she first burst onto the scene (to name one of many examples (as told by 1980s Rolling Stone magazine editor & MTV VJ Kurt Loder) in late 1984 she was promoting her Like A Virgin single & video in MTV's studios in New York where there was an incident where a staff member who was bringing her a requested specific coffee drink arrived back and as she was about to give the drink to Madonna; Madonna moved around and knocked the drink onto herself. So Madonna went into a fit of rage and insisted she would not do the interview unless that member of staff was fired. As Madonna was clearly going to be huge via her forthcoming Nile Rodgers produced second album MTV bosses insisted that the tearful young female be instantly dismissed.
Ironically, also in the MTV New York studios at the time was one David Bowie (promoting his quite frankly awful Tonight album, and doing advanced promo for his early 1985 single "This Is Not America". He, like Kurt Loder, and a number of MTV employees who were there that day were so appalled by Madonna's action that not only did he subsequently hire that female MTV member of staff (who worked with Bowie until after the Glass Spider tour ended in 1988).
It is fair to say whilst Madonna claimed to be a huge fan of David Bowie; that was certainly not reciprocated, as he has been on record to criticise her numerous times throughout his career (Ditto Elton John whose diva behaviour is matched and often surpassed by his apologetic lavish gifts). Hence in a famous 2002 Radio 1 interview when asked what he thought of "the Queen Of Pop" he said She's "The Margaret Thatcher Of Pop". As potential rivals Cyndi Lauper; Mariah Carey; & Lady Gaga all saw over the decades.
Talking of the latter; Madonna only got the 2019 ESC gig because allegedly Lady Gaga pulled out over Israel empowered by Trump's USA tearing up UN agreed Oslo Accords over the West Bank occupation.
Which is a pity as the 2019 ESC really could have done with having a world class music act (whom has already won 3 Grammys; 1 Oscar & 1 Emmy more than Madonna) who has already proven she can sing at the second & most watched annual worldwide TV events in tune whilst putting on a stunning performance, rather than the abject embarrassment we witnessed on Saturday night in the 3rd most watched worldwide annual event:
PS. Any Madonna fans I'd advise you to miss John Oliver's very latest Last Week Tonight show as he has brought up Madonna's career takedown of Lady Gaga from a few years ago "She's Not Me" and has thrown a few clips and reminders of the pair's high profile performances since then to highlight the chasm of differences between the two. He also highlighted a number of this year's ESC acts who were clearly inspired by Lady Gaga.
But as to quote punchline of his near 10 minute segment on it:
JO: Well Madonna was certainly right. Lady Gaga was no Madonna copycat act ....... as Lady Gaga can sing and act ..."