Depending on your level, you might want to look into graded readers. Tadoku has some free graded readers. I’d recommend going through each level until you find a level you’re struggling with and focus on that. They also have readers available to buy. If you know all of the JLPT5 grammar and some of the JLPT4 grammar, you could check out NHK Easier, a website that pulls articles from NHK Easy and makes it so you can hover over words to get their meaning and reading. If youre above a JLPT4 level, you could probably check out native material for adults, but you’ll likely have to look up a lot of grammar.
Either way, with reading, you’ll only improve with practice. I recommend getting into a habit with reading, doing it daily if possible. Even if it’s just reading a page in a manga or an article on NHK easier.