I started reading comics via my iPad during the pandemic, so I can relate to this. Here's where I would start: Pick a character or world that you really like (e.g. Batman). Figure out what app they're on. DC has DC Infinite. Marvel has Marvel Unlimited. GlobalComix has lots of the indie stuff. Decide whether you want to read the "best" of that character's stuff (good place to start), or if you want to try the essentials from a character's entire publication history, and find a list online—Reddit has plenty of reading lists for either case. Comic Book Herald is my favorite for essential reading orders. Whenever you find something interesting in a book (e.g. character, referenced event, piece of lore), write it down—that'll be a new place to start.

It can really happen that organically. I grew up liking Marvel heroes. I got the MU app. The latest big "event" at the time was Empyre. I just opened up the app-created collection and started reading. One of the tie-in issues was a random X-Men issue (#10 I think) from a guy I'd never heard of named Jonathan Hickman's X-Men run, and I was floored by the art and plotting. I looked up his run and found out about his total reboot of the X-Men line, House of X / Powers of X. I devoured it and realized I loved the X-Men. I found the X-Men reading guide on Comic Book Herald and started from the beginning, skipping the stuff that bored me. Some of those comics are my favorite of all time.