Crank no start, fresh battery, light amount of starter fluid started it. 2018 Elantra GT sport 1.6T

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I have a 2018 Elantra GT with the 1.6T. The other day I got a new battery after a no start. The week leading up I would have a rough the first time I started it in the morning, after that, fine.

Details

On the old battery jump starting it got the car to start, after that it would have easy starts and drive fine.

Got a New battery after this, hard start in morning afterwards fine, today no start.

Sprayed a little starter fluid into the intake and it started rough but started

Restarted the car again and easy starts after that

Spark plugs were changed 3 weeks ago, rougher starts started about a week ago

No movement of tachometer when sputtering trying to start.

No check engines, and my wife has the code reader in her car, so can't get that right at this moment.

The jump start getting it going a few days ago and the starter fluid getting it today throw me off.

Has anyone run into this before, advice, or thoughts as to the cause?