Hello and welcome!
The Google play store is indubitably the golden standard, includes the largest collection of apps with excellent security. Unfortunately it also comes with the caveat of needing to login to an account. Banking apps in particular may force your hand, apps can figure out what source they were installed from and refuse to run if they don't like what they see.
Aurora store is a front end to the play store which enables you to use it anonymously through provided throwaway accounts. These are being heavily rate limited at the moment, so in-app search is non functional, but there is an easy workaround available. Updates work just fine.
F-Droid, while popular, is considered insecure and ideally avoided: https://privsec.dev/posts/android/f-droid-security-issues/
Then there's Obtainium, not a store, an update aggregator. You tell it where to find your apps and it will notify you when updates are available and let's you install them right there. The downside is that your apps must host their apks publicly on GitHub and such, it can't scrape the play store (though it can search F-Droid).
Last but certainly not least, Accrescent. The next big thing, built with modern infrastructure from the ground up. Currently in early alpha, it's not yet a suitable replacement for any of the above due to its very small app repository, but it looks promising!