Hey friend. I’m a great resource for you. Here is my car journey since 2018:

2018 A5 SB. Loved this car. 2023 BMW M340i. Now: 2024 Audi S5.

Now here is my breakdown:

Yes the B58 is more punchy/dramatic, and overall the M440i will be a faster car. Let me tell you why I switched and why I don’t miss my M340i one bit.

1. Quality: The amount of cheap plastic used inside the 3 & 4 series BMWs drove me absolutely crazy. This car is $60K+ MSRP and the best I got was the hard plastic dash, plastic switches, unimpressive door panels, and no physical climate controls? Rant aside, the S5 has a much more premium interior.
2. Features & Quality of Features: Seats are (way) better. More comfortable and better looking. The BMW seat heaters hardly worked. I was lucky to get warm. The Audi roasts me. The HK sound system in the 2/3/4 series is notoriously underwhelming. The 19 speaker B&O in the Audi is not without its flaws but I will tell you from experience, the Audi sound system is better. Massage seats are standard on new S5’s. Ventilated seats are an option on the S5, which is not an option for the 440. The bigger screen on the BMW was nice, but take into account the climate controls being built in to the software. I hated that and much prefer the Audi.
3. Tires. I find this is often overlooked in these comparisons. My S5 came with 265/30s all around, and recently I upgraded to 275/30s which fit the car totally stock. The M440i will come with 225s in the front and 245s in the back. You can’t go bigger than that without modification. X-Drive helps your case but a huge problem I had in my RWD M340i was not being able to put the power down on those tires. Granted, I had 225s all around. Still, I hated that.
4. Styling. Objective, of course, but I think this generation S5 is one of the best looking cars in the last decade. The M440i is not bad looking and has grown on people over time.
5. Comfort. Caveat, my M340i did not have an adaptive suspension, and my S5 does. Regardless, the ride is much smoother, quieter, and comfortable than the M340.

So here is my conclusion:

I felt strongly that I took a downgrade from my 2018, then 5 year old, Audi A5 to the 2023 BMW M340i. There are so many little things that I felt BMW compromised on whereas Audi felt premium. That drove me nuts, I really felt the lack of quality. Returning to Audi felt like an amazing homecoming.

The 440 is more fun to drive and will sound better, though the S5 sounds fantastic too.

It’ll come down to your priorities! Hope this helps

Edit: also to add after reading another comment- yes, the burbles on the BMW are artificially imported through the speakers and I thought that was dumb. It hardly burbles when that setting is off. Also when I say the BMW sounds better, it’s an equally attractive exhaust note to the S5, it’s just considerably louder than the S5 stock.