2.25 lbs of steeping grain is a lot? I got a grain basket it all could fit in.
Steeping grains are typically to add color and flavor, and are usually in small amounts.
If you are only intending to end up with 4.5 gallons of wort going into the fermenter I would recommend that you scale your recipe to that volume.
My system only boils off about 1 liter (0.265 gallons) per hour.
Maybe this is where your issue lies if you think you are boiling off 1 gallon per hour, but you aren't.
Your boil off rate may be set higher than your actual = higher volume and lower gravity.
As mentioned, put a specified amount of water in your kettle, boil for a specified amount of time, and measure the volume difference to determine your actual boil off rate. Tee best way to measure your water before and after is by weight. Water expands and contracts with temperature changes, but it always weighs the same. One Liter of water = 1 Kilogram, or, one US Gallon of water weighs 8.34 lbs.
I am going to recommend that you take some time to go over the beginners guide here on Brewer's Friend, it is an excellent source of information for a newer brewer (rhyme not intended).
Brew, Learn, Repeat!
Homebrewing for Beginners: How to Make Beer at Home
https://www.brewersfriend.com/homebrewing-for-beginners/
