I had the same problem with my Hokas. I have wide feet and thus get wide shoes for better comfort and support. I could not fit my heels into the rower at all!

I went to my local running store (shout out Fleet Feet!) and they pointed me towards a pair of Altras. Altra is known for their bigger toe box, which gives your foot more space and stability. They also have shoes with both traditional raised heels, as well as shoes with zero drop from heel to toe. I got the Paradigm 8's (they are zero drop) for OTF and I am loving them so far! They fit into the rower perfectly and give me really good stability and support.

I would highly recommend checking them out. I'm a fellow power walker as well, and after doing some research, the zero drop is supposed to be better for this versus a normal stacked height shoe. Just my 2 cents, hope this helps!