As someone who has very casually self-studied Chinese over the past 6-7 years and gotten to an "intermediate plateau" (started as a digital nomad in PCR, then Taiwan, and then married my Taiwanese wife).

Since you've already learned many languages I'm assuming you are already familiar with what works for you -- for me I really resonated with the "fluent in 3 months approach" of basically just forcing yourself to consume as much content and use as much of it as you can (which I was able to do in Taiwan, starting with ordering coffee and working your way past the "where are you from" conversations).

I've always struggled with Chinese characters, however (I also struggled quite a bit with English spelling). I picked up https://www.outlier-linguistics.com/products/how-to-learn-ch... over black friday and have really been enjoying it. I'm not sure if it will resonate as much for a complete beginner, but with my limited experience it's actually making characters "make sense" for me.

ChinesePod has been fantastic for listening comprehension, and is also highly recommended.