Yes and no 😃
As @ralfkrause says, it is possible to build a 32bit custom MoodleBox out of the box, using a RPi OS Lite 32bit image as a basis, so yes…
…but I would not recommend to do it, as Moodle 4.2 requires a 64bit version of PHP, that needs a 64bit OS. So you would not be able to update your Moodle installation.
So if you would like to stick to Moodle 4.1, there's no issue with 32bit. However, I cannot see any advantage to do so, since 32bit only Raspberry Pi models aren't recommended at all to run a MoodleBox, and there's no performance gain for platforms that can run 64bit like RPi 400.