BT can do assault and have psyker support from Librarius conclave, but you have to take the Dark Angels version so you don't lose out on chapter tactics.
Here's a list that I think would do well in the environment-
Chaplain w/ auspex and digital weapons 100 pts
3x Ten man Tactical squads w/ grav cannon and melta gun in rhinos 660 pts
1x five man Assault squad w/ sergeant with powerfist in a razorback upgraded with twin linked assault cannons 170 pts
1x five man devastator squad in razorback with twin-linked lascannons 145 pts
10th company task force
3x five man scout squads w/ combat weapons in land speeder storms 300 pts
Now all of this will be apart of a gladius strike force. All of this comes in at around 1375 pts, giving you room for something like an Imperial Knight in an 1850 list.
Few things to note about this list I have so far-
It has a strong element of Objective Secured. It has 8 units starting on the table and it hasn't even hit 1500 pts yet. Standard battle company lists take the minimum required just so you can flood the table with as many cheap units as possible. I personally don't subscribe to this method for the simple fact that Kill Points games are an uphill battle. I'd rather balance out the amount of punch and durability with each unit, to better leverage my odds of doing well in either a kill points game or an objective based game. Scouts have more points invested into them than usual because now that scouts have WS/BS4 they make for a promising close combat element. The speeder storm comes equipped with a tool called the cerberus launcher, that if I recall, lowered leadership in addition to any damage it might do. I like this for the idea of a much easier combat resolution against nonfearless enemy elements.
The assault squad as well as devastator squad I felt only needed to be taken in units of 5 because 1, I feel that twin-linked weapon systems on vehicles are a better bargain than weapons you can give your units. You can give heavy weapons and evicerators to your assault squads and devastators respectively if you wanted to invest the points, but I feel points are better invested elsewhere.
Now, with 475 pts left over if you wanted to go 1850 (Ive noticed this points level seems to be the gold standard in competitive) You could like I mentioned previously, take an Imperial Knight, or even compensate lack of anti air with the air defense formation. I'd recommend against taking something like First company task force unless you dropped the transports from the scouts or just dropped the scouts entierly, because First company needs a bit of a points investment to make an impact. 5 terminators without a heavy weapon aren't really going to do anything other than tickle what ever it shoots at the moment it drops, 5 sternguard in a pod have a slim chance of putting a dent in something when they drop in, and Vanguard vets can look scary when they arrive. Realistically, these guys are assets you want to do a little more than just fire and forget. they're still space marines, T4, with a 2+ and 3+ respectively.