I agree it's odd that folks who use this software something that isn't a "competitive offering" may have to open-source their software stack if they upgrade to a new version in 2028. But, they will always have the option to use an older version of the software that is still covered by the BSL.
Except here thanks to the AGPL choice, it seems to be the exact opposite of an assurance: if you use this in a proprietary setting, you’re just fucked if the business is gone and the software needs patching.
This isn't like a service where they can try force you to agree to an updated EULA with some "by continuing to use this service…" crap, or a rented device like a "smart" TV that can effectively do the same by refusing to work (though technically you've already agreed to that with a "we can fuck you over at a later date" clause in previous click-through agreements.
I have nothing against AGPL, in fact if I relase anything I'll probably use it, but if I did dislike it, which some very much do, I wouldn't tough this with a bargepole even years before the change.