Quitting my per diem?

Newer nurse here. I have about 11 months of nursing experience. For my first 10 months of being a nurse I worked in a skilled nursing facility 4 days a week. I was considered "full time" and received benefits.

I got a per diem job working at a LTC facility for extra money in May and have worked about 2 shifts/month there as that's their requirement. It's OK but I'm not entirely crazy about it. There was a sign on bonus which was a plus and it contracted me to work for them for at least 90 days to receive the full amount. (August 6th marks my 90 days).

I recently just changed my status from full-time to per diem at my full-time job for a new job at a subacute facility, which I start next week. I felt like the environment for me to learn will be much better, etc. With this company, I am eligible to work the minimum of 3 days/week to receive benefits, which I need. They are paying me very well, so that's not an issue. I'm trying to decide if I should approach my DON in regards to my schedule and ask if I could start out at 3 days/week (8hr shifts), instead of the four we initially discussed, as I do have two other per diem jobs and am currently in school for my next degree. I figured if I work the three days at my full-time job I can work more at my per diems, and give them availability and compensate with the extra money. but I know that no hours are guaranteed at per diem and I could be potentially cut if not needed.

It was not my plan to have two per diem jobs, but the company offered and I accepted because I felt bad I was leaving at such a stressful time, I was an employee of 9 years, and they were short-staffed. I'm conflicted whether I should approach the DON at my new job about my schedule change, or if I should stay at the 32 hrs/week we discussed initially and quit one of my per diems? I obviously make more money at my per diem jobs, so staying at 3 days/week at my full-time wouldn't be a concern, but I don't want to make a bad impression with my new boss, nor do I want to hand in a two week notice to a company I have only been working for 90 days and quitting once I receive my bonus (it will make me look like I was only working for the sign on bonus and that's not true).

I don't want to burn any bridges, as I would want to keep my options open in the future with any nursing facility. But I feel as if I were to put my notice in, I may be burning some bridges? My family says to wait and see how I like my job before quitting any of my per diems, but I'm not sure what to do.