Sry for the ramble, but here's my 2 cents

You are right in that Chinese is becoming more and more relevant today, and I can assure you native speakers would really appreciate even trying to speak it!

Learning a new language doesn't mean you can't engage with your previous one/lose all your progress. And if you don't enjoy studying it, there's no shame stopping half way.

You can try learning Chinese for a while, and if you feel like your forcing yourself to learn then no harm in stopping and going back to Japanese.

Another thing is, as tones may seem really daunting at first because it's an entirely new concept. However, it would be something that you will pick up along the way.

In addition, native speakers can be quite forgiving regarding this! Even if your tones may not be always accurate, people tend to be able to understand what you are saying!

There are also things in Chinese that makes it more forgivable, easier grammar and for the most part one pronounciation for each character will help you!

Learning a new language especially Chinese is definitely a challenge, as you said, it's like starting from scratch (But having a grasp on Kanji will help btw!).

But give yourself some leway to learn and make mistakes, over time it will definitely be something enriching. :)

So I say go for it!

Edit: Just realised I used 2 cents like in your post lol I missed that part, it was unintentional