One trick I learned a long time ago is take a walk around the block in the morning before walk, and do the same walk in reverse in the afternoon.

It tricks your brain into saying "this is my commute". Ideally you have a work laptop or some such that you can take out in the morning after your walk and put away at night before your second walk.

One of my co-workers setup and office in his garage for this purpose. Even though he had an "office" of sorts in his house with his computer and all, it didn't provide enough separation to switch his head-space, especially because he'd potentially be in there on his computer for reasons besides work. So he setup a separate office with separate equipment for work. When done, he just leaves the garage. The point being the commute might not need to be that long. Just a signal to your brain your done.

I've moved from using geographical boundaries to separate work from non-work to using time as the fence. Work starts at a given time and ends at a given time, very few exceptions. Laptop lid opens, laptop lid closes.

It's worked out well for me, but I can understand it not working as well for others.