If you try the 1.4.0-beta2 version of Cryptomator for Android you should be able to open a Keepass file with write access and changes will be propagated back to the cloud as soon as you navigate back to Cryptomator by closing Keepass because Store changes on files opened with Cryptomator directly back to the cloud is implemented.
Using Keepass, I personally like the combination of a key file, a yubikey and the password 
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