How fast 55k transactions could take?

The Otherside mint of 55k NFTs got me thinking how fast all those mints could take, I mean, what minimum time we can expect to all transactions be completed in Ethereum blockchain?

I know it depends on various factors, such as gas price, type of transaction, etc, but I'd like just to get a better notion about the time that it could take.

Let's consider 55k different transactions using a default gas of 21000, and that there isn't other transactions being made on Blockchain during that time (yes, very unlikely, but just to clear the discussion). So the question is, how fast it would take to complete all that transactions being made at the same time? I did that simple math:

- each ~14 seconds a new block is minted on Ethereum - each block has capacity around 70 transactions (with a default gas of 21000), if everyone mint 1 nft at the same time (so 55k transactions), it could took around 785 blocks to finish the mint (70 transactions per block, so 55,000 / 70), so the answer is AT LEAST 183 minutes (785 blocks * 14 seconds).

Is that logic correct? If the logic is correct, and considering that a lot of other transactions exist on blockchain and are disputing for the same block, it would take even longer, but kind of surprise to imagine it can't take less than 3 hours to have that process done even when thinking in a super unlikely situation (when there isn't any other transactions on the blockchain).