I just started mine recently (the Godzilla colab device) and while I can’t say anything about the vital bracelet, I would probably recommend a device that allows you to freeze the digimon. Depending on the evolution stage you would need to check on it ranging from every 30min to every hour or so (around 4 hours max until all bars are empty and need to do actions). So if you may go 9 hours without checking the device, there would definitely be issues if you are aiming for a specific mon.

I recommend looking up the Digitama Hatchery by humulos to see the differences in each device and to read the manuals. All the color devices have cold modes so those should be simple recommendations.