I didn't see the game so can only speak in generalities rather than specifics.
There's a lot of sense being spoken across this thread and put together comes to the following conclusion
a) the recruitment since the first Summer up has been poor and lacking in direction. The 11 who played most of the second half of the first season up is better than the one we have 3 years later. That's a fundamental failure.
b) Linked to that it looks stale, it did last year. It's why Nuno went. What we didn't need is a manager doing a variation of the same theme. It didn't start that way, it is where we are now though
c) Bruno's in game management is pants, has been all season - even in games we've won like Newcastle and Everton at home, games we should have won comfortably and ended up clinging on
d) We have always been a wasteful side not taking our chances or gambling to create more, be that either players playing safe or us not playing in a formation which gets enough men in the box. We aren't ever going to be a team who scores many goals with that mindset. We have also always struggled against sides who just sit behind the ball and ask us to break them down for that reason
e) We overcame that on occasions with Raul and Jota, particularly when they played in a 2. The former scored goals from nothing and the latter was great on the break. Neither of those players are here anymore unfortunately one literally the other figuratively
f) Nuno abandoned what worked because he was seduced by Traore. We lost Jota because of it and we don't even have Adama now. Ridiculous at the time and hasn't aged better.
g) We are dull to watch and have some unlikeable players at the top of the pitch. 8thish would have been a good result at the start of the season, but you can't ignore the way it's played out to get there. We are likely lose at least 9 of our last 14 games. Go into the Summer like that with the same management team and core group of players and it's how teams go down. See Sheff Utd as a recent example.
h) You could sack Bruno, on balance I'd not be bothered, but we'd just get another Mendes stooge so is there any point?