Why should you worry if you know how to preserve and appreciate it. There are many ways how we can hide or put our seed phrase keys in a safe, maybe it depends on us.
Because I don't put them on paper to write them, all I do now is save them on my flash drive usb, well, in fact I have 3 flash drives and it's just hidden in a place that only I really know . I've been doing this for a few years now and so far so good.
A USB flash drive is not the worst method of a backup for your seed phrase, but i will still choose paper over it. USB flash drives have a lifespan, and even if it is not too short, it can become corrupted earlier on and you would lose data stored in it, which you can only recover most times with the help of a third party service, and that is not recommended because the data stored there is your seed phrase and it can be stolen by this third party.
Make sure your USB flash drive is not connected to the internet regularly, and it must be encrypted and a strong password set up. Paper backup seems the best to me, but since you said you use 3 flash drives, i hope you have not kept all these backups in one location, if you have done so, you should consider separating it in different locations.