I'd recommend Tachiyomi. It's a popular choice among manga readers. However, make sure to download it from a trusted source as there might be unofficial or modified versions that could pose security risks.
I'm not sure, as most legal and authorized platforms charge for accessing manga. But be careful with free apps, as they might be illegal or of poor quality.
Mangatoon is worth trying. It has a decent collection and provides a smooth reading experience. Some of its features like bookmarks and recommendations are quite handy.
Tachiyomi could be what you're looking for. It's customizable and has a lot of sources for free manga. However, it might require a bit of setup to get it working just right.