My almost 3 yo is not toilet trained

I feel like a horrible parent. We've had many constiption issues and trouble resolving them. We've tried literally almost everything Our kid makes bird pellet poops and now we do enemas when things get bad. I suspect we both have anxiety around pooping although I try to be patient understanding and kind, as the primary caregiver.

I know it's not her fault but then it must be mine. I go down a rabbit hole of what am I doing wrong, why can't I get this right, and I know diapers are probably compounding the whole problem because at this point she hates not wearing them.

I'm alone as SAHM and have no help, which means I do all the cleaning cooking and caring. If she has an accident, it's on me to deal with. I'm also WFH and feel stretched so thin. I can't get additional help most days and feel so trapped in this situation, as a failure of a parent. I then have to hear about how she's behind and why aren't I doing something about it. She's in diapers all day and rarely wants to use the potty. I don't insist because I don't want to run into constipation. But then she's constipated anyway.

On and on it goes.

Help.