Hi, 700k mastery velkoz main here (d5, so effectively plat 1). Looked over your op.gg and saw a few things right off the bat. It appears you're liandries rushing in every single game, which is not a good call. Second iteming it should be a very rare choice against like, Cho mid. Velkoz has a very adaptable build path; when behind/against super squish teams, you should be rushing a morellos with your sorc shoes. Against mr stacker, you can even third item a void staff. You can also high AP rush or defensive rush with banshees/zhonyas.
There's also the glacial augment build which is 100% abusable before it gets nerfed, glp into twin shadows into pen. Midgame this gives you a lot of safety against anyone running at you, and makes landing your combo on speedsters like jhin very easy. I'd recommend trying it out in a few normals first, as it is a massive difference in feel. You come online pretty quick but your damage gets really tied to your 3 stack ult, so landing abilities on those slowed targets is mandatory.
I also see that you q max every single game. While that's good for supportkoz, in mid you may want to consider w max in some lanes. W max let's you instantly wave clear much sooner, giving you shoving priority. Against a bad cser like lebonk it provides some safety (but WARD!) and it gives you the opportunity to roam. You do have some losses where you got fed and weren't able to convert, if this was laning fed, then the extra roaming power of w max will allow you to transfer your lead to at least 1 other lane, making them less heavy to carry later. Note that you will have less 1v1 power in lane with this build.
If you're getting fed in Midgame and aren't able to convert, then it's probably your positioning. Unfortunately, velkoz does not have the same Midgame poke as other artillery mages like xerath and lux, your q is quite slow when fired off at angles to get max range. Yes there's a temptation to move up next to your frontline to poke at their backline, but the moment you become your teams fed midlaner it's your job to carry fights, not start them. Unless you can make a lethal catch on a carry, sit back, be a little less effective prefight, and then use your fedness to annihilate both tanks and squishies since now you're alive and properly ranged to hit both when the fight starts.
Just kinda hit the high points there, anything specific you're looking to improve at? (also, suppkoz is way better than its win rate imo, but it is a very big play style shift, so while I do recommend it for climbing, it'll take some practice in normals to get used to it)
