If you're using off-the-shelf "hidden" encrypted volume schemes, you're not going to be evading state-level adversaries; if you can find these projects and conveniently use them, state vendors can and will write scanners that find them. They're paid to do it; new detections are how they get to charge for maintenance and new versions.

Then you're down to two issues:

(1) Concealing an encrypted volume jacks suspicion way up; whatever pickle you were going to be in if you just kept an encrypted DMG on your desktop, you're trebly in now.

(2) Your actual security comes down to the strength of the encrypted volume, and this is 20-year-old encryption. He can't use a memory-hard KDF because of his BOM, which, like, fair enough, but that doesn't change the fact that this KDF is probably ~50x faster than standard bcrypt hardness and on realistic human passwords is probably crackable in minutes-to-hours on a dedicated rig.

I winced particularly at the observation that the hardness was set where it is because of how long it takes to open the encrypted volume on this hardware, because whatever scheme is being used to run the KDF now, an attacker won't bother; they'll just copy the bits and attack them on serious hardware.

Point (1) isn't meaningful if your adversaries aren't states. It might make sense to have a hidden encrypted volume for the same reason you'd want an encrypted safe. But point (2) applies to everybody.