Learn the Nashville numbering system. As for solos -- You can do scalalr like pentatonic , learn minor, major scales and mixolydian scales and you are off to the races. The remember riff makes the solo meaning the rhythm. Then leanr to solo over chord tones and to simplify this the most powerful chords tones are the 3 and 7. Then learn II, V, I turn arounds and you make this interesting by altering the 2 and the V7 chord notes. Add a little chromatic tones and you are on your way, And remember the blues. Of course that can take a year or years but it really is not that complex, The diminished scale will be the icing to provide tension and simply make it interesting. This is just not for jazz only jazz musicians think they are the only one doing it,I am generally a rock and county bassist. I do like metal too, but the gigs I play are in the rock/country world.
As for my struggles, when I say memorize I mean that I just can remember a song starts on a certain note and I know what comes next. but I don't really think about it as "ok this song is a 1,3,5" or whatever. It's like a muscle memory thing without understand the reasoning behind it...if that makes any sense at all
BUT always play on time. Never falter on your time however beginner or advanced you are. Play with Joy and if it's the blues - remember it's about a good man feeling bad -- if that is your foundation then your soul will connect to your listener.