So, i loaded up your map and here are the issues:
No idea why those bunkers are missing textures (from the screenshots they appear to be metal bunker walls from frontline, and they are the only texture not working here.
But thats not the main issue. First area is HUGE and has zero cover, meanwhile red has all the cover,including bunkers to snipe every single living thing from.
This slope is really steep.
These traintracks look really weird, also train crossing sound is completely glitched out and is playing super fast.
There is an invisible wall here with nothing to mark this is the end of playable space.
This sightline is so long that far-z clipping plane starts chopping away its far end when you stand at either end. The same goes for the path on the opposite side of the map.
This is another very long sightline.
This area inside of the building(?) is a completely confusing maze. Confusing players is bad.
The cart goes through this gap? Are you sure it can even fit through there? Cart can push people into the wall if it goes really close to one.
Again, another large area with no cover and invisible map boundaries.
Look at official maps for reference on area sizes, sightline lengths and how layouts are designed to funnel people towards the objective.
I know that you think that D-Day beach assault is cool but it definitely wont be in TF2. Running out of spawn into a flat area with zero cover with 10 snipers shooting at you is the antithesis of fun.
I tell you: come to TF2Maps group chat, queue your map into the bot, talk with people there, and get it tested for feedback after you fix these issues.