There is the older version as described in my above post - It's what we all used before Homegroup, and by many instead of Homegroup. There is a basic tutorial (offsite)
here which should get you started. Each of the component parts are covered more fully in our own tutorials.
You would as you say need accounts on each machine and manually set share and File permissions, but with careful, (Creative?), setup there is no need to have the same user on every device - simply set the shares to everyone and if you wish turn off password authentication as proposed above
You you can use the Public "User" who's files are shared automatically with everyone
As this Workgroup networking has been in use for many years it's possible that you may be able to share with your wife's machine directly, but best to check with Mac documentation
Microsoft would prefer, (I believe), that you use their OneDrive system to share files, (but why use the internet to share a file to someone 20 Feet away
)
Another method is a Bluetooth Network Which can really work well if you have Smartphones and tablets but is still not simple to set up
Additional - One other issue that affected the withdrawal of Homegroup was that it Relied on IPv6 which needed to be turned off in some markets as it caused issues with various system processes