In 2019 I finished my mathematics degree and decided that I wouldn't immediately apply for graduate school in 2020 as I want to take some time off for both personal and practical reasons. It's not like I won't be productive as I have a job and some small projects I want to get rolling but beyond that, I'd like to know if there is anyone with similar experiences and/or ideas to stay engaged in mathematics.

I'd personally like any book recommendations that cover mathematics at the advanced undergraduate level but with some generality as a way to stay engaged with algebra, analysis, and topology at a level where a master's degree won't be too hard when I decide to get started. But a general discussion about what to do after undergrad is appreciated.