How do Chelsea, Newcastle etc get round the Fair Play rules

Newcastle haven't actually been spending that excessively.

And Chelsea aren't really getting around it, they are just pushing it down the road. The contracts they are offering will actually make offloading players really difficult in the coming years so they will end up struggling to sell the level needed to keep themselves under the max losses at that point unless we see something happen that suddenly sees an influx of cash as they will need to keep the accounting surplus every year and as they aren't likely to not sign players for the next 5-8 years the amount they need to sell will just increase.

Oh and it's not like accounting practices cares about the real world cashflow issues. They may spread a transfer over multiple years but book the whole amount on a sale but they are still running in a negative cashflow by hundreds of millions, eventually money will run out as their sources of investment to cover it will stop lending. So even if they can sell enough to cover the amortised amount there is only so long they can borrow the cash to keep themselves liquid