My take on the players that you mention:
Duran - I was a supporter for a long while, thinking his speed was valuable, especially if he could hit anything like his minor league example. First time up he was extremely strikeout prone. The second time up he was better about pitch selection but his swing is long and he isn't getting hits out of his contact. His shaky defense hasn't improved. At his age, it appears we need to look elsewhere.
Downs - He has shown defensive abilities but hasn't hit in the minors and is lost in the majors. Perhaps we should give him additional time in thee minors and see if the lightbulb comes on. Otherwise, he is no major leaguer.
Cordero - Some power but a very poor hitter who is also a very poor defender. Let's move on as he is not going to help the team to be competitive.
Dalbec - He has power and has had his moments but doesn't appear to see the ball that well. He has had enough time to demonstrate his hitting which is not good. He is a still defender at first an doesn't move well enough at first. Another guy that we should move on from.
Refsnyder - He is an older guy who couldn't make it with other teams. Of the lot he appears to be the best, but a utility role should be his limit. Good enough to hang around with a low salary commitment.
We don't have much time to wait before the trade deadline and we see what Bloom is intending to do. Probably sell. If that is the case, why not bring up Casas and others and jettison those that won't be with the club next season. Perhaps that causes a money issue that I don't understand, otherwise bringing up prospects and getting a look makes sense. If we can make a decent trade for a ML player or prospects, fine. Let's start looking to 2023 and beyond.