Wow, well, I must admit I was unprepared for this, and I do apologize I didn’t make the deadline.
But thank you for your excellent response and for nominating me.
That said, the honest truth is this is probably the messiest and least efficient area of my digital life.
But here goes a brief overview, definitely a work in progress, and hoping I can make it better soon! (certainly working on it…)
Consumption
Web Content - articles, emails, etc.
First and foremost: open tabs in Chrome until I read them
with things saved to Pocket and/or Instapaper being lost for the time being 
Occasionally I’ll save an email in my inbox unread to remind me to read something in it.
Meanwhile I am trying to start using Notion to save articles to, I love it in principle, but the clipper is not yet as good as I would want it to be. I do collect recipes, particularly cocktail recipes, and while the clipper is not great, it is adequate for this purpose, especially since cocktail recipes are typically short and even when poorly formatted, they can be read. Would still like significant improvement here though.
I take notes on articles on occasion, usually for now still in dedicated pages in Quip, though occasionally in Roam (which I mostly only use for a daily log).
I have lightly experimented with Worldbrain’s Memex, but it hasn’t “stuck” yet.
eBooks
What are these again?
No, really I don’t have a good means of reading eBooks (not going to do it on my phone or computer), so I don’t do so right now. But I would like to one day.
That said my dead tree book reading is pretty slow as it is (due to lack of applying time to it, another problem I’d like to remedy). So this is just something that needs more time investment…
Audio
I listen to both audiobooks and podcasts. For audiobooks it’s just the Audible app, and I don’t make the most of it. I’d like to actively take notes or something, but I don’t… yet. One of those habits I plan to adopt and develop a workflow for (suggestions welcome!).
Sometimes I’ll take some basic notes, but I’d like to have a more regular note-taking and review practice.
For podcasts, I was perfectly happy with Google Play Music, but Google killed that. For some reason I don’t like Google Podcasts as much, for one thing it seems to do a bad job of maintaining which episodes I’ve listened to. 
I had never heard of Airr and now I wish it were available for Android! The idea, at least, is excellent. Of course some podcasts are available on SoundCloud where audio highlighting has been a thing for years (and highly underappreciated/underutilized IMO). But I’ve signed up for the notification list on Airr so will definitely be checking that out when available.
Not sure if music counts, but I had to switch to YouTube Music and it kind of low-key annoys me every day. But Spotify annoys me more, so… Also I’m a YTM subscriber, so no ads, etc., which is only part of what puts me off Spotify. Anyway, I have 1 or more newsletters that send me new music either daily or weekly, along with other sources of new/interesting music. And I have special playlists and a workflow (however primitive) to save promising new songs, review them over time, then promote to “favorite”, or file into a “keep but not favorite”, or remove from consideration. Still the list tends to only grow…
Video
I watch a lot of videos on YouTube. I have a fairly large amount of subscriptions, but only 8-10 set to actually notify me (the bell). Of those I watch about 75% within a couple days, leaving them as browser tabs until then. I don’t let my notifications pile up, I clear them out at least once/day, otherwise they’re hard to manage.
I do take basic notes on my video watching when appropriate, or just save a link to a video, depending. Video links will generally be saved in relevant pages in Quip or Notion, e.g. I have an entrepreneurial reference folder in Quip, so if there’s a good video on sales or whatever, I’ll put it in the Sales page, maybe with a few quick comments.
A lot of cocktail recipes also come from videos, so sometimes I’ll just save the URL and thumbnail to the same Notion DB with all the others from web pages.
Social
I don’t have a specific workflow or tool to save Tweets or other social content yet. Sometimes I’ll save a link to e.g. a specific Facebook post or Tweet in a relevant page as above (e.g. entrepreneurship), or I’ll quote it, or just write notes inspired by it.
Frankly the fact that readwise replies in the thread on Twitter drives me crazy and makes me think that either Twitter (most likely) or Readwise are broken and hacky. I don’t think I’m willing to subject others to that given how much it annoys me
so I’ll probably just stick to Memex or Notion clip/highlight options until something better comes along (Codex?).
Storage and Retrieval
I touched on a lot of this above in pieces. In short, I have most of my legacy content in Quip, use Roam for daily logs and some brief notes, and am adopting Notion for more and more, mostly database-oriented stuff. Also testing Anytype and kind of hopeful it can replace Notion soon-ish. I have Readwise, but don’t use it yet. I probably should before the trial runs out! 
Phew I’m sure I’m forgetting something but that’s a lot for now. Hope it was interesting! I know it’s a mess, I’m really between lots of tools right now. If you asked me the same question a year ago it would have been much cleaner, though at the same time I’d say my process for e.g. collecting cocktail recipes is actually easier and more efficient in some ways now. That’s really the purpose of adopting these new tools, I just have so many parts to my workflows, and content in legacy systems that needs to be migrated, so it all takes a while to settle down…
I’m going to nominate @Calhistorian (Mark Robertson) both because I’m curious about the workflow(s) of an educator who does research professionally, and because I know him to be an extremely thoughtful and interesting person from Twitter, where we’re already casually acquainted.
I’ll go hound him over there if necessary. 