Chinese native speaker, pretty good at Japanese (passed N1 many years ago). I actually think spoken Mandarin Chinese is a lot easier to learn for most situations except for a complete beginner:

• For a complete beginner, Japanese has one of the (if not the) fewest possible valid pronunciation among all languages. There are literally only ~50 "alphabets" (officially only 48, there are a few weirder non-official ones), all of which are easily pronounceable. Mandarin Chinese also has a pretty restrictive pronunciation set, it's simply that the tones (especially the 3rd) tend to trip ppl up
• Past the complete beginner stage and Japanese becomes noticeably more difficult than Chinese. Japanese grammar is an absolute nightmare, and you do have to know most of the grammar rules; not to mention you can have multiple different ways to pronounce the same word... Whereas Chinese has almost no grammar and overwhelmingly relies on memorizing vocabs, which someone who only wants to speak doesn't even need to worry about how to write them (which is most of what makes it difficult)
• Just to clarify, both Chinese and Japanese are high-context languages (to compensate for way too many words sounding exactly the same), so the fact that a local might not understand you often has less to do with shitty pronunciation, and more to do with that the entire sentence makes no sense. A lot of Chinese ppl understand regional dialects (which are pronounced very differently) just fine

The Chinese dubbed anime thing is for Chinese ppl too. JP has a very robust seiryu (voice actors) industry, and a lot of CN/KR dubs just simply can't catch up with the voice-over quality... A good example, think Genshin Impact: it's a Chinese game but the default VA is JP. I highly doubt this has anything to do with the language themselves. The language themselves... I've heard some ppl say that spoken Chinese sounds "angry", might have something to do with the tones. Not sure about Japanese...

Japanese has fewer sounds, and as an Indian I can already make most of them. On the other hand, the grammar is very subtle and tricky.

As for how they sound, I would say that Japanese sounds warm and energetic, while Mandarin sounds soft and polite.

It depends on what you already know, if you don't know any tonal language already then learning your first tonal language will obviously be an additional hurdle.

That said, Chinese is considerably easier to learn than Japanese in many other ways, such as the basic grammar being remarkably straightforward.

Japanese is way easier. Mandarin is tonal and if you don't have an ear for it, it is maddening to talk to natives and they can't even guess what you're trying to say because you can't tell that you're using the rising time instead of the flat high tone.

Personally, I also find the tone restrictive since atonal languages can use musicality in speech as another dimension in emphasis while that would muddy meaning in tonal languages.

That said, Japanese is hard in other ways, but those hurdles are when you get closer to fluency

Having learned a lot of Japanese and a little bit of Mandarin, I'd say that Mandarin is easier overall. Pronunciation might be simpler in Japanese, but the grammar is much more complex.

I've never learned Japanese, but I found Mandarin tones very easy to learn. You learn how to say the word one way, one time. Whereas with Japanese, the way you say things changes based on context, and it's going to be hard for a foreigner to learn that. Either way, you're not going to sound natural as a speaker if you start after childhood.

In addition to being more familiar due to anime, I find Japanese easier to listen to (although I don't understand much) because when transliterated into English it's quite easy to pronounce the words once you get the hang of it. Not even considering the tones, I think there are just fewer sounds in general and they're all easy to learn. It's not hard for an English speaker to understand what words are being spoken even if you don't know what most of them mean.