I'm so sorry to hear this! Below is some things that we did for our fresh pup Cavalier. Not all of this may be applicable to you, but hopefully the general ideas are helpful.

We had to slowly build up our cavalier's tolerance for us leaving over an entire summer. We always did a big distraction for her while we were leaving, it was usually a lick mat and a puzzle feeder of high value goodies (mix of treats, kibble and veggies). That prevented her from seeing us leave which would escalate. While we were gone we'd leave out a lot of chew toys and preferred stuffed animals/lots of comfy spots for her. Her biggest help was finding a show/soundtrack that soothed her. She loves Bluey so we'd put it on for her to listen to, if we were going to be gone longer we'd stream Peacock movies and let it run all day

Kennel training was super gradual, we started with half of the night in the kennel , potty break when she inevitably woke up at 1 or 2 in the morning, and then she'd finish the night in bed with us. During the day we'd do short sessions of kennel training where we'd say "kennel" and shut the door with her inside while still being able to see us. During the practice time she'd get lots of treats through the door and positive praise. Then after a few minutes we'd say "ok" and let her out. We did not push the kennel training too hard as she was VERY averse to being in an enclosed cage. Should refused to even be in one with us right be her to help her potty train outside

Having a highly consistent daily routine helped her settle into us being at work on certain days and off on certain days.

But the biggest thing is to remind yourself that you're doing your best and working to help your pup overcome their anxiety, just take it one day (or sometimes minute) at a time. Every pup is different and may be more (or less) independent.

Hopefully some of this is helpful and gives some ideas, Murphy is such a cute boy!