Yes, I installed box86 & box64 via published package repos.
For box64 I installed the box64-generic-arm package.
Then ran the install_steam.sh script and then installed some missing dependencies after.
apt install libsm-dev:armhf libgl1:armhf libxinerama1:armhf libxdamage1:armhf
As already tested, Thimbleweed Park works just fine. Was hoping to run Return to Monkey Island but it wont display graphics yet (launches and audio plays to a blank screen if you install the mesa-vulkan-drivers package).
I’m out of disk space on my SD card, otherwise I’d try Portal 
If steam still doesn’t work for you, run /usr/local/bin/steam with BOX86_LOG=1 and install anything it complains about being the wrong ELF class: ELFCLASS64, meaning it’s found the 64bit version of libraries installed, you need to install the armhf builds (ignore the libpng12.so.0 one, you’re not going to satisfy it)
You will need a swap device configured with the 4GB RAM CPU module as it’ll leave very little RAM free (less than a 100MB) and swap out more than 3.5GB.
After the install, you’ll want to pin the reform-debian-repo to arch=64 to suppress apt complaining there are no armhf packages found there (it’s non-fatal, just cosmetic) from then on.
Your /etc/apt/sources.list entry should look like this
deb [arch=arm64 trusted=yes] https://mntre.com/reform-debian-repo reform main