Michael Sanders2 wrote:
Substitute "approve", by "Apple-signed KEXTs".
Technically speaking, they are "approved" by Apple somewhat. Apple approves a developer's application for a kernel-signing entitlement. The idea is that known malware developers would be rejected. But kernel extensions are such a pain that it is unlikely that anyone would make one maliciously. They are definitely not signed by Apple. They are signed by their developers.
I have no idea what "modern" versus "legacy" KEXTs are, but these are all extensions from software applications released within the last 1-6 months.
Apple officially deprecated kernel extensions in macOS 10.15 "Catalina". They were replaced with something called "system extensions". Unfortunately, in all of its user-facing apps and documentation, Apple calls them all "system extensions". But they are very different.
Apple has been discouraging kernel extensions for some time now. In some cases, they are outright disabling them if a true system extension could do the job. But in many respects, there are about as many user-authentication hoops to jump through with a system extension as there are for a kernel extension. Apple allows them, but a developer would have to have a really, really good reason to make a user approve them.
And finally, to address your original question, or statement, rather. This is not a bug. It is by design. I could have gone to even greater lengths to describe the social and financial pressures that Apple is putting on third party developers to steer them towards games instead of system utilities, but I thought that you had probably heard enough. Rest assured, I only scratched the surface. This is yet another aspect of that. It is even fully documented by Apple: Kernel extensions in macOS - Apple Support
To paraphrase that document, one or more of your kernel extensions are making the operating system suspicious. It has decided that your operating system is no longer full secure enough for credit card processing. Note that this may not actually have anything to do with Apple's discouragement of system utilities. This particular "feature" could be a regulatory requirement from the credit card industry. It might even be preemptive compliance. The credit card industry doesn't move very fast, so it is in Apple's interests to avoid giving them the opportunity to arbitrarily Apple disable kernel extensions at some point later on. Plus, it coincides with Apple's efforts to discourage system utilities anyway, so what's the harm? To Apple, I mean. If there is a conflict between some freebie or cheap 3rd party apps and financial services revenue, who do you think Apple is going to side with?