Over the last couple of years, my greatest learning ally has been the O'Reilly Learning subscription.
Although the default pricing of $499 per year is a pretty tough pill to swallow, with an alternative path you can get a much better deal that I personally think is totally worth it.
The amount of content you get access to is insane. I can probably count on one hand the times I wanted a book and it wasn't available on the platform, and that's definitely its strongest point.
I'm more of a heavy book user, but you also get access to audiobooks, courses, and articles on the platform, which increases its value even more.
The mobile app itself - funny enough for a company teaching you how to build software - doesn't feel that great to use, as it has lots of small performance and UX issues, but still works "well enough" to get the job done.
Of course, all the content you get is in digital form, so if you like physical books, that is something to consider.
How to get a better deal
The Association for Computing Machinery has an add-on to their regular Professional Membership that includes access to the platform for just $75 USD.
This is added on top of the annual subscription cost of $99 USD (or less if you're in a developing country), but even so, you get ACM membership that allows you to read the latest research while also having the O'Reilly platform for around $175 USD.
Considering that a single book can cost around 5,000 to 10,000 JPY in Japan these days (even more expensive if you want the original English versions), I cannot recommend it enough. Just get it.