I have a list of all my subreddits as RSS feeds. Did some text transforming to add the RSS links and used an OPML generator to make the file. I was not adding 600+ subreddits individually, lol.
I've collected loads of RSS feeds, from Congress (bills and other happenings, etc.) to the NY Times, and Science Daily with their topic feeds. GitHub has a few OPML files, though some of the feeds are out of date. Tumblr used to have a way to export your followed blogs as OPML, but that broke at some point in 2020. Mastodon has RSS feeds for every profile, but it's a pain to collect, as their CSV export outputs the address in the wrong format for the feed.
I use Feedbro on Firefox, and QuiteRSS & RSS Owlnix on my Windows desktop. I also use Podcast Addict on my phone for my podcasts and keep a copy of the OPML file in my RSS reader as backup.
KeePass with Keepass2Android on my phone with the vault synced via Dropbox. Use biometrics to access both apps. I also use Secure Password Generator on Firefox to get passwords + several options in KeePass (readable passphrase, diceware, etc.)