I find it best to read documentation and seek out good textbooks. This can be tiring, but the trick is to put zero pressure on remembering or understanding anything - there's no exam!
Lazily scanning through every setting in a configuration file / function in a library / flag in a compiler e.t.c. will go a looong way! You will be amazed at how much you recall when you get stuck.
I recommend learning some C (don't worry, it's small!) and doing an embedded software project (I highly recommend the Raspberry Pi Pico!). Much of modern programming practice is arguably a reaction to the decades spent doing similar tasks with low level languages and low-power hardware. Experiencing this really helps to contextualise things. I guarantee you won't look at your laptop / phone / washing machine the same way again :)
Some of my favourite and most rewarding tool choices have been in direct defiance of my prejudices. In fact, nowadays I actively recommend trying something utterly bizarre (like vim) on the off chance you fall in love (like I did, with vim).
Enjoying a tool is important. If you find that you do, use that energy to learn it inside-out :)
Honestly, thinking about recommendations with hindsight is tricky. Much of what I have learned was motivated by aspirations that have long since changed.
If I met my past self... I doubt I could convince them to relax, ignore what's trendy, and do more aimless studying!
TL;DR: just focus on changing your perspective, you will gain confidence over time :)
For specific recommendations, check out my books & links page.
My main machine is a Framework laptop. I love it.
I used to buy relatively cheap gaming laptops, but I often found myself disabling the discrete GPUs to prevent excess heat and power consumption.
I hope to keep my Framework for as long as possible, perhaps upgrading to a RISC-V CPU years from now :)
I have a Pinebook Pro. It's really nice to use. If I only did systems programming, I would probably make this my main laptop.
I use an ErgoDox EZ for typing. I like the keyboards on my laptops, but the EZ helps with my RSI.
It also encouraged me to improve my touch-typing, and use a more code-friendly symbol layout. I got the blank key caps, and labelled them with marker pens :)
I have a small Wacom Intuos tablet, which I use for digital modelling / painting. Blender is really powerful with a 3-button mouse, and my stylus has two thumb buttons which are great for RMB / MMB mapping.
My phone is a Fairphone 3 running iodéOS. I mainly use it for instant messaging, 2FA, or listening to music. I love what Fairphone are doing, but I hope to ditch Android someday for a more flexible mobile OS. The Pinephone Pro looks promising.
I love using Raspberry Pis for things. I have a Pi 3+ with a DAC board running Pianoteq. It can turn any midi keyboard into a great sounding piano!
I keep an Arturia Minifuse under my laptop. It has a USB-A hub input on the back so effectively uses no ports. It's fun being able to record guitar quickly, and makes a big difference when working in audio software. I don't use it if I'm just listening to music though, as it drains more power.
For photos, I either use my phone, or an Olympus OM-10 35mm film camera.
For videos, I use an old Canon EOS M with a cheap CCTV camera lens, running Magic Lantern. I used to use a 550D (Rebel T2i in the US), but the EOS M offers similar quality and is much smaller and cheaper.
Oscilloscopes are wonderful. I primarily use one for making audio electronics, which has relatively low frequency requirements. Two channels is nice, but not required.
Make sure you understand how to not blow up your scope!
Most analogue audio projects require bipolar ±12v power! It's safest to set this up so that 0v is tied to earth ground, but this requires a dual output supply which can handle negative voltage.
Moritz Klein has a great tutorial on creating a simple synth power supply. This is great for powering finished projects, but a proper lab bench power supply provides desirable prototyping features, such as short-circuit protection.
I use the Hakko FX-888D soldering station. Soldering is deceptively difficult, especially without enough heat!