I don't have a good suggestion for holding the solder and iron in one hand, but if you search for "soldering helping hands" you'll find a variety of tools for positioning the board you're working on.
My local library uses overdrive for ebooks, which you can check out and either download for kindle, download as epub, or read online in your internet browser. I usually download to an eink reader, but if I'm reading on my phone I use the read in browser option.
Suggestion: if you plan to read on your phone, look in the settings to set the background and text color of whatever app you choose to something that doesn't strain your eyes.
Download + offline listening is also something I look for in a music app. I just went through the free trials for deezer and qobuz. Deezer's download was straight up stupid - I couldn't find a way to force it to immediately download updates after modifying a playlist. With qobuz you could force the download immediately, but it makes you select "download only" before you start the music, or it defaults to streaming. Every single time. Sometimes the playlist got corrupted too if a song was removed. I'm almost ready to start buying music again...
I came across this giant comparison table of eReaders last time I was researching an upgrade. While it doesn't list supported file types, anything running an android operating system that lets you download apps for reading from google play would meet your needs.
I'm not too familiar with what loom knitting results in, but my guess is still crochet. You can see where the yarn is twisted into a taller stitch (knitting tends to use many small stitches instead to create patterns) and how the stitches aren't exactly aligned (taller crochet stitches sometimes slant when you turn the work). Compare the back of the couch (it's oriented the same as if you were actively working on it) to this: (https://nordichook.com/wp-content/uploads/2023/09/PinVID_Double_crochet_blo-683x1024.jpg)
Hiking. I don't try to climb mountains,just get out and move. The fact I have to watch my footing and have a chance of seeing (or at least hearing) wildlife helps distract from the fact exercising sucks.
I use mental tricks as well. I had to bribe myself to get started. "Look there's a trail near that takeout place you like, if you hike you can get takeout!" If I run out of breath due to uphill terrain, I'm not stopping because I can't keep going, it's clearly to look at this neat bird/bug/plant. If I have an off day and need to turn back early, I remind myself that I've already won by getting off the couch.