Cady doesn't seem to want to work in L.A. full time. She's the artistic director of a theater in New York and is fully committed to that. When she decided to do that, it seemed that Missy Reeves might return to Days eventually on an ongoing basis. (I don't know what's happening with Missy now.) Cady's LinkedIn profile says she started that at the theater in January 2022.
Edit to clarify, Missy had come back to Days for an arc at that time.
Cady and Jon Lindstrom (her husband) have residences in New York and Calif. She can work on Days sometimes because Jon's on GH, but from their instagrams you can see they periodically spend time in New York. Jon plays two major characters on GH and he's been there for decades, but he's not on contract, so I guess he likes flexibility, too.
The Cady situation is different from that of Ali Sweeney, but there are some similarities. Sweeney's focus is that she acts in and produces lots of Hallmark movies, which are usually filmed in Canada. She's willing to stop by Days between movies.
The six-month tape-to-air gap allows for some flexibility for shortterm returns, or if someone has to reschedule their scenes due to COVID exposure, or if they are using a special set for a story arc.
I doubt they could write invested longterm story for Jennifer or Sami - if the characters are in a pairing or pairings because they'd have to write around the actresses' schedules - even with the flexibility of the tape/air gap. It would make romances seem disjointed. I think they can allow pop-ins if someone's not in a pairing. But if someone is in a pairing but unavailable, it's hard to give the couple airtime.
They tried to accommodate Chandler working fulltime in Georgia, by arranging for him to tape a Days arc when he had a few days off from work. He said he had a workaround where he sometimes brought work with him to LA - in that he got up very early in the morning and worked remotely from LA on his laptop, and then went to the studio to film all day, but it made for very long days working both jobs. When he did that, it allowed his taping arcs to be a little longer - to squeeze in a few more episodes. But he couldn't work both jobs the same day for extended periods of time. I'm glad they tried find ways to accommodate Chandler but it still made it difficult to do a full WilSon storyline.
Back to Cady. I'm glad she's available sometimes, but I just don't know what the show can do with the character of Jennifer in larger storylines.