BD1791 tollyboy [...] but it appears he is no longer making belts.
A few months ago, he was still here. 😁 (Cp. https://unwedchastity.org/d/611-tollyboy-odd-jobs ) IIRC, he was about to relocate his business to Europe / Austria (?), but I don't know the current status. Hopefully he is well; ( @Taz ) hope we get an update, when the time is right.
BD1791 Neosteel offers an upgraded lock that's supposed to be very difficult to pick. I'll probably opt for that one.
Alternatively invest into more padlocks to change from time to time, plus a bunch of unique plastic seals that your keyholder signs and applies when maximum protection against lock-picking is needed. Might depend on circumstances, particularly your time, opportunities and skills for lock-picking, though.
Updated (2022-06-12 18:49 UTC): I should add, we have some experts on lock-picking at UWC, too. 😁 I'm almost sure they will be able to give a much more qualified evaluation on the intricacies of current Neosteel locks.