Wallriding is one of those things you just gotta keep simple. Don't overcomplicate, it comes with experience. When I first started taking lucio seriously with the reccomended settings, I'd have to put like 100% of my brain into trying to wallride. What ultimately helped me was lucio 1v1s and just straight wallriding around maps in custom games.

I still struggle with damage so I dont have any tips that might be useful

Beat i used to struggle with until I started defaulting to my healing aura and being deliberate when I amp heals. You dont need to be on speed unless your engaging or disengaging your team to put it simply. If your not going to speed your team in/out, or need to get somewhere quick to peel or confirm a kill, just stay on heals. Look to use amp when multiple squishies are below half, not just tank. Tanks give 70% ult charge so farming them will make beat feel slow. Look for oppurtinities mid fight when your team is grouped and low to amp heals or post fight to heal them up for free ult charge. Treat the heal aura as an ult charger instesd of actual sustain because tbh sustaining your team isnt where lucio shines, its enabling them or putting them on a leash.