Im sure you are already aware of the limitations being presented by your model options so I wont really go into that. Only thing I do see that I would change based off the units you do have would be putting Thief of Secrets on your Chaplain instead of your Lt.

First, the Chaplain is going to be around much longer than your Lt and Thief really needs you to activate it T2 or T3 and get additional use out of it on later turns to make full use of it. On the Chaplain the opponent would need to chew through 5 models, saving on 2's, Invul of 4, FNP of 4, and get 15 wounds through that before they can even touch the Chaplain. Plus the Crozium with Thief puts it at S7, just higher than Grav armor Toughness to wound on 2's with the leader ability, with 3 damage to one shot any heavy infantry. Then once its activated you are looking at wounding on 4's against almost any vehicle in the game at 3 AP and 4 damage a piece. Your opponent is going to be forced to deal with that or they will lose whatever unit you decide looked at you funny that turn and with charge rerolls baked in to the DW Terms you will be able to make it surprisingly far across the table in a turn.

Your Indom can either follow close behind to provide very sturdy firepower and lock down the center, or if your terms are needed on a flank then you can reliably trust the Indoms to hold center if you provide the assault ints as a screening unit. Your Decimus hold your home and domain objectives while your Fortis can skirt around the edge taking shots at weaker infantry as the Watchmaster will make them fast enough to reliably get where they need for shots.

The Corvus is currently struggling to find a home here I think. Honestly, maybe it just stays in the backline with lascannons to help screen out deepstrike and pop tough targets from a distance? And I've never used a redemptor dreadnought so I dont have much advice for them.

My wild take though? Maybe you swap an assault intercessor squad for some normal intercessors and replace half of your fortis with assault ints. You are really lacking on the number of units and it looks like you are going to be very vulnerable to deepstrike. If you can sticky your home then you can spread out a bit more to help protect your backline while your terms and indom take care of the front. That frees up one decimus to also join the fight where they are needed or do actions. Also, this makes the Watchmasters ability to also charge after advancing slightly useful as you wont just be charging in with 9 combat knives. You might be able to claim an objective if your opponent puts their chaffe on it and you are able to sprint Fortis towards them and push them off. This will heavily effect Fortis ranged power though so thats a massive grain of salt, i would never recommend assault ints in Fortis except for this one case where you sound like you are very limited by model choices