I don’t know about Rocket Japanese, but I’ve heard some snarky comments about JapanesePod101 not being worth the money given its content (not necessarily here… might have been on Twitter). I’ve never tried it myself, but I haven’t seen that much promising content from JapanesePod101 being shared or popping up on my YouTube feed. You might find a few of their explanations helpful as a beginner, but that’s about it? That’s my impression. Up to you to try them out to know for sure. (Or you can wait for more comments, of course.)
For grammar and vocabulary on YouTube, I’d suggest Real Japanese with Miku or Japanese Ammo with Misa. Probably better. However, they’re not really immersion material? They just give you lots of little examples and explanations. (Still good, but not necessarily what you want in terms of ‘listening and speaking’ practice.)
For written explanations, Maggie Sensei and Wasabi Japan are pretty good in my opinion. You can also try following teachers on Twitter or Instagram since they often post useful vocabulary.
If you want some short simulated conversations to practise listening and speaking, you can try the material from NHK:
I think it’s pretty high-quality, though it obviously doesn’t cover all the Japanese you need to progress from beginner to intermediate. It’s more like… decent practice and application material? Mostly pretty basic – the Kanji Dojo explanations go relatively deep into etymology though – but that’s OK if you’re just starting out.
Now, most of this stuff focuses on polite Japanese, and that doesn’t necessarily sound like how Japanese people usually speak to each other every day – textbook Japanese is often a little more polite than typical polite conversation – but you can worry about more casual Japanese around the intermediate level since polite Japanese is what you’ll use with most people until you know them better. I mean, of course, Japanese kids learn casual Japanese first, and I think knowing ‘plain forms’ for verbs helps with understanding grammar, but most resources for beginners (Genki included, if I’m not wrong) start with polite Japanese, so you’ll have to work with that for a bit. Just learn how to convert between plain and polite when you start learning conjugation and you should be fine.
(To be clear, I prefer using the plain forms as a base and working from there, and that’s how I would teach somebody, but even I learnt polite forms first – it’s just that plain forms got introduced pretty quickly after that in my textbook, and I went and read up on plain form conjugation after that, so I could switch ‘base forms’ in my head.)
