Disclaimer: I am not a strategist or even good. Since it is a 4v4 you wont get any good advice
I gave the match a quick watch. You seemed to be carrying the team for about half the match. Two guys were slow getting their stuff on the field (AFK). Both right next to you. Most of your plays looked good to me.
One problem was your right side mate was an offensive player. These guys blob up and smash into the enemy, do damage, then retreat. So they have a great score but hold zero points all game long. You guys got your side and your game fell apart when you went middle because your mate could not hold the side.
On Port of Hamburg south, you have to hold the right side. North has to hold the left side. If you lose your side you get opened to flanks and have few areas to hide your army. And artillery becomes very effective. Also if your front line has not changed much for several minutes expect artillery spam. I think you had a werfer and one guy had an LeFH.
The enemy held the left fuel all game and took your fuel when you went mid. So they had fuel for days which means big tanks spam.
I don't think you could have done too much differently. Maybe fortify your side more before pushing the middle. 4v4 also means you need commanders with Lefh for side play and elephant for middle play? Several times your blobs got stopped by MGs but you did not put many MGs around your side late game to stop the blobs coming at you. One MG could have slowed them and then a werfer shot to rek them while suppressed may have helped hold the right side late game.
Maybe spread your volks out a little so when you hit an MG you dont have to retreat the whole blob.
4v4 randos is hard. Early you stole an MG and popped in the building by the bridge. At this point you probably felt like these guys were noobs and it was won already. Which is sometimes true. But sometimes they are good and just retreated to keep their army and you get rekt when they come back because you didnt respect them enough

Also that building has a sight blocker to the enemy side so it does not cover well for you.
Good Game