That is interesting indeed. What I don't understand is that if S17 will do approx 42 TH and all the 4x 3080s will do a combined 360 MH, shouldn't the S17 be mining a lot more coins? The value of $9.20 usd / day for S17 seems too low or this is how things work? I thought, the more the hashrate, the more the coins mined.
You're comparing two different hash rates. The S17 will only mine SHA-256 coins. Because of all the ASIC miners tuned to this algorithm, the difficulty on those coins is higher, so it's harder to hit a block. The GPUs can mine a whole range of coins that ASICs either don't exist for or aren't widely used. That means they could take advantage of any market imbalances between those altcoins they mine, their difficulty, and their sale price.
Ultimately, if you want to mine Bitcoin (and this is the Bitcoin mining forum), you need modern SHA-256 ASICs. Your limits are going to be your power costs and space availability, since a single newer ASIC is going to eat around 3 kwh per day.