How can I select all photos from the Photos app in iPhone?

The iOS Photos app doesn't let you "Select All" like the MacOS app does. I ran into this issue multiple times, and it's problematic when I need my libraries to not be synced because my iPhone keeps complaining about space. You can only do "Select All" from an album, not anywhere else on the app.

The answers from Apple have been to just "Select" and drag your finger until you get to the end... which can take forever if you're dealing with more than a few photos. But today I came across a Reddit post that had the perfect solution, so I wanted to post it here for future reference since the previous post on this topic is closed:

You can do the select option place your finger down starting on your newest photo first and get it to where you can drag to select photos but leave your finger on the screen. Then use a different finger to tap the top of the screen so that it automatically goes to the top of the album and selects each photo. Might lag a little if there’s 15k

*****

Hope it helps!

[Edited by Moderator]