Mazda6 2009 Starting Issue

A few weeks ago it started with a couple stalls at stoplights. Car started back up no problem and ran fine with no issue. Last week my son left the radio on and it killed the battery. After recharging it started stalling a lot, running reallly rough and stalling became more frequent. Starting was very slow too, which I attributed to low battery after being drained. The slow start persisted along with the other issues as well. Yesterday, stalled on the road and slow crank would not roll enough to start. At this point I’m thinking the battery isn’t that old but the drain might have prematurely killed it. Installed new battery and still slow start but it started up once, then it died and a couple more slow cranks then nothing. I charged new battery to be sure it had good charge, then tried again. Right now the dash lights up, sounds like maybe the fuel pump primes the system and that’s it, still no crank at all. I can hear a very slight humming sound if I put my ear close to the engine while the start stop button is still on. It goes away when I tie. It off. Any ideas?
 
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