.symtab and .debug_info sections in libgo and gccgo binaries are intentional, go unfortunately isn't able to deal with stripped or stripped to file executables or libraries. Missing .gdb_index must be some GDB issue, perhaps it gives up on Ada debuginfo. The Wbidi-chars tests intentionally test how the compiler behaves on the problematic Unicode chars. If it would be possible to waive some of this and be remembered for all future gcc builds, I'd waive it somewhere, but I'm certainly not willing to waive it for each single build when it reports the same things again and again.
Note, the PR104099 change just buys the basic_json using packages some time, as nothing changed for C++23 which requires the behavior that gcc previously had for older standards as an extension. So at latest when g++ switches to -std=gnu++23 by default (right now the default is still -std=gnu++17), it will not work again.