Magento 2.3.x and below doesn't support anonymous classes

[indefinitedevil]

Fixed in magento/magento2@e165d99#diff-eac375a5ebf2447976201de8fbe0bd0d04ce9798bc0e49c573e8d755317dac22

Basically, as it stands, the DI compiler for versions below 2.4.0-p1 doesn't support anonymous classes and so any compilation which uses Hyva Admin will fail due to the anonymous classes used in the factory models.

[Vinai]

Thanks for bringing this up, @indefinitedevil
I'd be willing to merge a PR that extracts all anonymous classes into named classes, but at the moment I don't have time to do it myself at the moment.
My first priority in my open source time is to get admin forms support working.
After that I would circle around to this issue if no one has beaten me to it by then.