You can’t run unsigned software on Apple silicon. Note that when you build your software if you use Apple’s tools it will inject an ad-hoc signature into the product.
You very much _can_ run unsigned software on Apple silicon. At work my department has a bit less than 50 engineers with Macs (M1 to M4) and nobody complained that they can't build and run our product (using GCC from Homebrew, not Clang from Apple). But it involves some jumping through hoops, yes.
As mentioned above you have to approve the binary two times (at least), being careful the first time because the dialog popup offers to remove the binary. Also since our product has some networking to do one has to mingle with firewall settings to allow the binary to do the networking.
To check I did this: removed the signature (LC_CODE_SIGNATURE section) using lief Python package (no affiliation, just looked suitable for the task), checked by otool that the section is indeed gone, started the binary - it worked. The spctl said that the binary is "rejected", but it says so about every non-Apple binary I checked on my machine so not informative. The codesign tool shows "is not signed at all" on the binary with stripped signature.
I'm not too well-versed in OSX system/dev tools, so if there is a more correct/precise method of checking the signatures I'd very much like to know.
The signature that gets added is vaguely a hash of the binary. You probably want to look at the UUID that gets injected into your binary instead of this.