Hm, do you know anything about Arnold and Murtaugh than what is commonly known (known, not opined)?
From what I can see, Arnold has been involved with a finacial side of the club that has been running magnificently, and then as a CEO overseen Ten Hag take over and been responsible for securing Lisandro Martinez, Casemiro, Antony and Christian Eriksen (plus Malacia and Dubravka) in one window, which certainly isn’t bad, and taken a few positive steps in regard to improving the disastrous relations between club and fans. That looks pretty well so far to me.
Murtaugh has been responsible for structureing the Academy, which has improved since then; the women’s team, which has a wonderful development; the data analytics side, which is too early to see results from but which certainly was important to do; and started onrestrictureing the scouting system, which ditto can be said about. He has backed Solskjær to second place and EL final, removed Solskjær after two months of dismal form, brought in an intermediary which many had wanted as both sporting director and manager previously, to kickstart a much wanted modernizing of direction, gotten probably the best available candidate for new manager ahead of all other clubs, and has been sporting director behind getting in Varane, Sancho and the above mentioned players. I think it’s fairly well indicated that Tonaldo happened against his wishes and over his head. Everything hasn’t worked, but most certainly has, and I’d argue we are looking better as a club going forward than we did when he began in his current position.
Looking further down, it seems you want to criticize him for Solskjær without giving him credit for Ten Hag, which is strange, as he inherited Solskjær (and fired him) while he chose Ten Hag.