Mag oxide and Pre/Probiotics

I’ve been on low dose of MiraLAX (1/4-1/2 cap usually) and mag citrate (calm) for 3.5 years now after childbirth to prevent fissures and keep stools soft and also not strain (I have pelvic floor dysfunction esp when stressed).

They work for me along with my diet but I really don’t want to take something artificial if I can switch. I’m looking into switching from MiraLAX to Mag Oxide and adding in a pre/probiotic. However I am terrified of stopping my regimen since it’s prevented me from ever being that constipated again and retearing. My constipation is pretty well managed with diet but hormones and stress and my straining with the PFD really do create harder stools at times. So I’d like to stay on something still for a while that’s more natural.

Is there a mag oxide dosage/supplement you all recommend similar to MiraLAX that I can take that’s helpful? What about pre/probiotics. For me not straining is the biggest hurdle since I have so much trauma from all of this so I just need softer stools when possible and to keep things predictable.