Hindering small transactions and repeated transactions

Here's my ideas. I don't have a super in-depth knowledge of how Nano works, so feel free to tell me why I'm an idiot and why this won't work. My idea is based on limiting the number of transactions that one can make with a given amount of Nano by limiting small transactions and repeated transferring of the same funds.

  1. POW difficulty increases as the transaction size decreases. This would only minimally affect good-faith users, as few people ever have a need to transfer $0.01 of anything. They would still be able to of course, but it might take a little longer. The function of POW difficulty vs transaction size would adjust automatically according to system congestion, so under normal network conditions, all transactions would have the same, low POW difficulty.

  2. Implement a short cool-down time for transferred funds before they can be transferred again. The cool-down time would adjust based on the status of the network, so there would be no cool-down during normal conditions. What I'm thinking is this: You have 100 Nano in an account and there's a cool-down time of 1 second. You transfer 10 more Nano into the account. You would be able to transfer 100 Nano out without any penalty, but if you try to transfer any more than what was in the account 1 second ago, your transaction won't be processed until after the cool-down. Taking that approach, rather than essentially locking an account every time it receives a deposit, would prevent an attacker from slowing down someone else's transactions by spamming their account with small deposits. Honestly it's hard to imagine even a 10 second cool-down causing a huge inconvenience for normal users.

For an attacker, there would be some sweet-spot where they can cause maximum disruption for a given amount of funds. They would want to split up their funds up in order to produce more transactions, as lots of small transactions will be less affected by the cool-down, but they wouldn't want to split them up too much or else they're getting slowed down by the increased POW difficulty. I haven't done the math, but what it would come down to is that you'd need X amount of Nano being used against the system to cause a significant disruption. If it's possible for the math to work out to where X can be prohibitively large without the penalty parameters crippling the system, it could work.

But again, I'm not an expert on the inner workings of crypto so I don't know how practical this would be. I'm already imagining a few potential flaws, some of which I have ideas to mitigate, but this isn't meant to be a fully developed solution so instead of laying out every detail and possible scenario, I'll just leave it at this for now and see if it goes anywhere.

Hi there and welcome!

It's a good idea to aim at limiting the number of transactions, because the network can only process so many and prioritize if the transaction limit is exceeded.

Do I understand it right that you're essentially arguing for an additional multiplier on top of the one from the dynamic PoW that depends on the transacted amount?

That's a powerful measure to limit spam, but currently the network has no sense of time. That needs to be added in one way or another, but can be done.
Taking time into the equation is part of the PoS4QoS proposal, too.
Have you found that already? It's very similar to your second point.