How do small coins cope with hashrate jumps/drops?

Hello,

I have now experienced a few times that smaller coins (I've mostly looked at Cryptonote coins in that regard) suffer from sudden jumps and drops in the hashrate, particularly when the hashrate jumps to a 50x+ value for a while - taking the difficulty with it very soon - and then drops again - leaving the difficulty far too high for a prolonged amount of time (which, for me, smells like someone taking advantage of small coins by suddenly launching a huge amount of hashing power to it, making some quick blocks, then when the difficulty adjusts, they go away and to the same to another coin, leaving their victim coin users with multi-hour block times for a long time).

Also, this of course means that a coin suffering this kind of "attack" also gets into a >51% situation with the whale, and on top of that I've also once seen confusion and chain splits because at day 1 of a coin launch with a super low initial difficulty of 100 or so (from a test someone did on a weak machine), people dumped 200KH/s onto it and we got millisecond block times and a big mess.

Is there some kind of counter-strategy for this problem? I was wondering about this for a while and didn't find much info about it.

What about all those small Cryptonote coins, do they just cross their fingers people won't do this to their coin, and if it happens, they sit it out and get 1-hour block times for a few days and then hope it won't happen again, or what?

Thanks!

EDIT: Follow-up question: Would reducing the difficulty window help solving the problem? For example, having a CryptoNote coin which uses the last 8 blocks instead of 720 to calculate difficulty. It would appear that this would help, but it then makes me wonder why most coins I saw didn't have a low setting like this (Monero also has 720). I guess with too low a value, difficulty would be even more unpredictable - but what is too low?