09 Tahoe New battery, new starter and alternator is good amd car still wont start

I have been exhausted troubleshooting my 09
Tahoe that wont start and by process of
elimination (and watching countless you tube
videos) I am desperate for your 2
cents...instrument panel lights up but none of the
gauges work in the car will not start the windows
go up and down randomly the locks work
randomly the stereo stopped working but it used
to go in and out and I get it to start maybe one in
a hundred times of sitting there and just trying
over and over and over the little light with the car
on it that means the car is locked I guess locked
out or whatever stays on continuously it doesn't
flash or blink. I'm a single mother who's been
sitting here working on her own truck for weeks
trying to figure this out and just got a new battery
two days ago put in a new starter have the
alternator checked checked all the grounds put
new terminals on the battery cables and use
brass I feel like the problem is in the steering
column area which brings me to the security
switch and the ignition from what I understand
these are problem areas but I don't know if the 09
Tahoe even has a passkey or how the I don't want
to cut wires unless somebody's telling me this is
for sure the answer because again I'm not a
mechanic at all I'm just mechanically inclined
have no money and I'm determined to fix this
myself if I can. Please any help you can offer me
would be gratefully appreciated as my son is
walking to school in the pouring freezing rain
everyday and home and we are having to Uber to
the grocery store the laundromat and it's getting
expensive I can't do this much longer is there a
mechanic Angel out there somewhere.