I was going to say use the old timey fixed width typewriter fonts that the US Army Corps uses (PDF page 5 and beyond), but I guess that they’ve switched to Times New Roman.
Maybe use open source fonts like DejaVu and Liberation?
I was in a similar situation. Not sleep-phones, but just a particular type of headphones that I like. Have you thought about getting a Bluetooth receiver for them? It’s super annoying, but it’s the only way I’ve been able to keep my headphones. Just thought I’d suggest it if you hadn’t thought of this solution/kludge yet. https://www.fiio.com/btr3k
The other option is to get a USB-C adapter. https://us.creative.com/p/sound-blaster/sound-blaster-play-4
Once I started using the tool lending libraries in the San Francisco East Bay, it was a game changer for simple maintenance.
Some bike shops also have public work benches with tools. https://www.boxdogbikes.com/about-1