These are my opinions, not a security expert or anything but - if your system is compromised two layers won't make a difference. If someone gets ahold of the KDBX, two layers might slow them down but if they have the compute to crack the KDBX in the first place a second layer won't make a difference, even if you're using a stronger algorithm.

I can only think of two benefits.

1. using two different algorithms adds a layer of protection in the event a flaw is discovered.

2. If it's wrapped it would likely have a different extension and signature, so if someone were to say, hack the cloud storage provider and grab all the KDBX files you might get missed.

In any case, the encryption algorithms we use today will likely be irrelevant and useless at some point in the near future. If you suspect your KDBX has been stolen, you should change all your passwords - even if they can't crack it today, you don't want to get an unpleasant surprise in a decade because you didn't.

Although changing your passwords on interval is a good security practice anyway.

I also wouldn't sync them with a cloud storage system either, since you never know.