As a user of Qt and the STL, I'm missing an equivalent of find_first_of and find_first_not_of in Qt APIs

I am tasked to make our base64 en/decoding routines available also to our Qt users in our company. That's easy enough, but then I wanted to port my test. In it, I need to limit the memory, so I don't want to keep an "expected" string in memory at the same time as the result of the test, so I'm basically doing

std::vector<std::byte> input(2GiB + 1); // all NULs ...
auto output = b64_enc(input);
assert(output.size() == expectedSize);
assert(std::string_view{output}.find_first_not_of('A'), std::string::npos); // ... encode to all-'A's

But I couldn't find the equivalent of find_first_not_of in QByteArray. Ditto find_first_of.

Please provide them.