If you were just talking about an electronic door strike, quite a few community members have used those, they don’t have to be expensive.
If you want a door which will actually open, not just unlock, then there are systems made for people in wheelchairs which again are not that expensive, The trick is integrating them with smartthings, but that can also be done.
Look at the quick browse lists in the community – created wiki, near the bottom of the page for the project reports section, and choose the “accessible” list for those discussion threads.