Oh I see.
I experience the same issue with Bluetooth devices. If I press a key on any Bluetooth keyboard, the system fans will spin and the wake process will start, but there will be no image on screen. If I use a USB keyboard, then it works every time.
UPDATE: Just tried waking system with a brand new Keychron K1 V4 bluetooth keyboard (currently sold out on Amazon). It works perfectly with Fenvi FV-T919. I am typing this from the Bluetooth keyboard after wake-from-sleep, which means Bluetooth devices reconnect automatically.
The most reliable wireless keyboards and mice for this system are Logitech wireless keyboards and mice using the Logitech Unifying USB receiver. These devices work in BIOS, in Clover, in OpenCore, and in macOS. They work with sleep and wake as well.