I agree with Jays. If you want more learning materials (as in, not native material), then I would recommend Shinkanzen Master, along with YT teachers like Nihongo no Mori who dive into N3/N2 grammar. Those same resources have N1 material as well. Bunpro is another option as a grammar resource.
Eventually though, and ideally alongside of your studies, you should be using native material. You can certainly start now. There are resources out there that are N4 level (Genki II + Tae Kim) that you can use for practice/study. There are graded readers, Satori reader, NHK Easy, and just Google searching for N4 reading/listening practices will definitely get you more.
There are book clubs on here that are aimed at various levels of difficulty. Those would very much be worth looking into. If you don’t want to do a current book, I would highly recommend going through one of the older books already finished. They have discussion threads you can read through or ask questions on if you need help.
Italki and Hello Talk are also options in terms of production practice. (Reading/Listening as well, but the main idea is to get a conversation going.) People join those places of all levels, so you can start at any time.
My personal recommendation, based off my past experience, would be to start native material sooner alongside your studies, rather than waiting. I kept putting it off thinking I wanted to know more first before I dove in, but I regret that. Take it slow if you need to, if things are complex, but it’s worth it starting now.