So for a long time now I've been a guitarist-poser. I.e. I can technically play the guitar fairly decently, but I've never taken the time to learn scales and such, only improvising what feels right.
As a result of that, things get very samey and stale and it severely limits my capabilities and abilities to write compelling material and I'm sick of it.

So I figured it's time to learn some scales. The problem is, I don't know where to start. So I will ask you guys what you think are the most essential scales that I should start with.
If it's relevant, I can say that the kind of music that I want to play is a melodic kind of metal with leads that have an uplifting, bright vibe to them.
Like the 3:12 part in "Late Confessions" by Dreamshade or the intro to "This Momentary Bliss" by Soilwork.

https://www.youtube.com/watch?v=rOKot58eYRM


https://www.youtube.com/watch?v=LR2C2kEONIU


Any suggestions?

it's not so much about the scales and modes. it's more about understanding how the chords work with each other and then choosing an appropriate scale to go over the chords, for example an uplifting solo in e major over a typical thrash riff in e minor will not work because in your riff you might have a G which will sound really dissonant with a G# in the solo because of the semi-tone interval, but what you could use is a G major scale over it since they have the same notes, because the aeolian (minor) is a major scale mode,

i'm too lazy to explain it all

For starters, just learn basic major/minor scales and improvise melodic lines over chords/riffs. Just practice that first and learn variations such as harmonic minor, melodic minor blahblah after that. Don't rush it. Work on your sense of phrasing and hearing (whether something fits or not) before worrying about theory, I say.

That's the most convoluted way I've ever seen this explained. Better off looking up "relative major/minor".

And in your first example, that lead is just played in a regular minor scale. What's making it sound dramatic is the chord change underneath. From the root to a minor 6 is a very typical modulation that newer bands use a lot. You could play any note in that scale as the chord or riff underneath the lead and it would sound good. I guarantee you once you learn that track, you're going to hate bands like soilwork lol.

^ About the Dreamshade song, that's right. It's just repeating a 3 licks over the chord changes, rather than utilizing any sort of more complex theory. It also sounds relatively good because it's played with conviction and decent phrasing, which goes a long way in guitar solos.