2012 Kia Optima EX won’t start sometimes

I have a 2012 Kia Optima and had the engine
replace a little over a year ago because of the
recall. I also had them replace the starter at the
same time. A few weeks ago I was getting ready to
leave out of town and had put some things in my
car and my car alarm went off. None of the usual
measures would get the alarm to go off so I had to
eventually disconnect the battery cables until I
could get back and find out why it was happening.
(Took my old Sorento) as soon as I hooked the
cables back up the alarm sounded again and still
nothing worked to get it to stop. Eventually I was
able to get the alarm to stop by putting the fob in
the charging port. Since then it has been going
dead for no reason. It won’t start as if the battery is
dead, though all of the interior lights work and dash
lights come on. But my car won’t even try to start
unless I get it jumped. Now my fob seems to be
intermittently not working. **note** since having my
engine replaced I’ve noticed that it often doesn’t
immediately crank when started. Instead it will
sometimes kind of sputter before turning over. This
never happened before having the engine replaced.
Also my interior lights have always flickered since a
few weeks after buying it in 2015. Any thoughts or
suggestions are appreciated:)