As far as I'm concerned, programming certificates are at best a neutral indicator and at worst a negative indicator. I've seen this opinion elsewhere, so I know I'm not alone in this. In general, they seem only to measure a candidate's ability to memorize facts and do little to measure their ability to think about problems in practical or abstract fashions. I.e. they indicate that an individual is able to pass a test, but do little to indicate they actually can use the language in question to solve problems of any real complexity.

Honestly, there are only a few certificates I feel hold much weight, and they are largely based on heavy practical focus, e.g. the upper-level Cisco exams. They're not much better than most certificate programs from the "pay-til-you-pass" perspective, but from what people I trust on the matter have told me, they're pretty damn hardcore when it comes to knowing the subject matter. I've never seen anything akin to them from the programming side. I heard some murmurs about the C++ Grandmaster Certificate a year-ish ago, but I don't actually know that it's any better than any other certification.

You've recommended C/C++...

No, I recommended C or C++. This is a critical (though pedantic) distinction.

Though their problem-spaces often overlap and people do group them exactly as you have, they are very distinct languages that share superficial semantic and structural similarities. Properly-written idiomatic C and C++ look/feel wildly different, and it's important to understand the differences between the languages from both historical and practical perspectives.