I am trying to learn playing guitar (electric in my case) and I got to the point where I can play minor pentatonic, blues scale, ionian (C Major), dorian and aeolian. Those are the usual ones I try to use just going up and down the scale linking the roots along the fretboard for different shapes and play along online backtracks. I am not crazily fast and I just try to stick with the rhythm. I learnt to bend, pull, hammering, etc, but I feel stuck now. I am not sure what to do next. I like mostly rock and metal (some pop and blues too). I admire heavy metal guitarist shredding and doing crazy things but in my situation what would be a next natural step to suggest?
Do you just "go up and down the scale" w/o any musical context? Learning scales first, and that's what it seems like you are saying, probably isn't necessary. A better approach would be to learn some songs that you like that are not too difficult. That will give the scales context. Musical patterns are more conducive to learning than straight scale exercises.
But now that you have some scales I'd say learn the chords that are embedded in the scales, how scales are connected, and how to relate a scale or mode to a chord.
For example the seven modes and seventh chords are related in key to the notes of the ionian mode in the following way. We call the ionian the major scale and its notes degrees (1 through 7).
(Degree, Chord, Mode)
(1, Maj7, Ionian)
(2, min7, Dorian)
(3, min7, Phrygian)
(4, Maj7, Lydian)
(5, dom7, Mixolydian)
(6, min7, Aeolian (minor))
(7, min7(b5), Locrean)
For example in the key of C maj the D dorian mode is just the same scale starting on the second degree. It fits over the D-7 chord. Even though this information is more used by jazz musicians rock musicians use these chords and modes too.
This type of information makes what you've learned more compressed and easy to access, imo.
You want to learn the basic ways to play each chord, not just power chords. To this end there are 5 basic chord forms that look like the 5 open string chords C, A, G, E, and D, and is sometimes called the CAGED method. While a lot of players think it's out of fashion I think it is very useful and I'm glad I know it. You can find the chord forms in any beginner book.
As for shredding, you need way more than just scales, you need focused training on your left and right hand skills. You need to look at body mechanics to shred. To that end learning sequencing patterns on the scales you already know and learning to play them in multiple ways is key to shredding. Also, learning arpeggio patterns and techniques like sweeping and consecutive picking.
You may want to start working through a book like Speed Mechanics for Lead Guitar by Troy Stetina, or anything by Kevin Dillard.
When you can do what you say, the next step is to find others to play with. Form a band.
Guitars are one of very few instruments which can be used for ingle note playing and chords. So make yourself familiar with chords. Major, minor, dominant 7, major and minor 7, will see you through most pop type songs.
In this band, there may be another guitarist, with whom you ought to share playing. Some lead, some rhythm. The rhythm will probably need some work: playing by yourself means not having to keep good time, and stopping when you've done something odd. With others playing, it's a different scenario.
Learning all the scales is fine (don't forget major pent and blues!) but that's only the alphabet. Tunes use scale notes, sure enough, but now you need to work out how to use those notes in any other than ascending/descending orders, to make tunes, and play some of those notes with some chords, and others with others. Good luck!
If you can play scales, that's not much. Think of it this way: a keyboard player gets the scales of the white keys as given. They also get the pentatonic scales of the black keys as given. Hit only white keys, or only black keys ... good music? Scales are just a frame of reference to build actual music on. For some reason, guitarists think that they have achieved something if they can play a scale. I don't think keyboard players consider it much of an achievement if they can refrain from touching black keys. ;) (partly joking of course)
So, what to do now? Raise your perspective and start operating in the domain of musical ideas, instead of instrument-specific technicalities. Melodies, rhythms, harmony progressions, songs. What kinds of songs do you want to play? Which musical role would you like to do next? Rhythm and accompaniment? Lead lines? Can you play melodies by ear? Can you accompany songs with chords? Do you have a feel for what individual notes do in chords, and how they change the mood?
Pick a song you like and learn to play it on guitar by ear. A looper pedal might be a nice thing to have for practicing, so you can accompany yourself and feel how the different musical roles interact.