I want to try Yoga after seeing this. could I just find any youtube instructors and follow along, or is it important to find "the right ones"? How would you approach starting out (must be online, wife won't let me leave the house because of covid)?
For an absolute beginner, where I have no idea what level of fitness you have or what injuries you may be working with, I would recommend Iyengar. It is relatively gentle, and emphasizes careful development. A lot of people like Vinyasa, which can range from slow and gentle to as aerobic as running. I like Ashtanga, which is about doing the same set of poses every time, but doing them correctly. I wouldn't recommend it for absolute beginners, however.
Obviously, don't run out and do crazy stuff like headstands or intense backbends or balancing poses unless you have experience. But also be aware that even "normal" yoga can have positions that are risky for people when done incorrectly -- for example, men typically have tight hamstrings and hips, and compensate in forward folds by bending over from the lower back. This can be dangerous if you don't have a strong back (and it's never a good idea). It is helpful to have 1:1 instruction if you don't know the form.
If you want someone who I know is a good instructor and willing to teach via video, please backchannel me and I can recommend.
For me it is not really a class anymore but supervised yoga. An instructor that walks around and helps me with my asanas and gives me hints to improve (aka Mysore). I can recommend it but it may be that instructors in Sweden are a bit more laid back when it comes to the weird stuff. And i can filter it anyway, when they talk about energies flowing through your head maybe they just wanted to say "keep a straight pose, it is good for you".
It really does wonders for my lower back. It just loves that kind of twisting and the core strength that comes with it.
But when I do it at home I use this one from Lesley Fightmaster. https://youtu.be/2wYN1IhnXT4
Yoga is great for core strength, getting rid of back soreness, and gently improving flexibility.
You'll also learn about your own body and develop greater self awareness when moving. Just take care that, though the risk is lower, you can still injure yourself by overdoing it. Listen to your body along the way.