Separate from people above having trouble connecting via Polygon. 

There were a few stories such as the one linked below regarding Coinbase being likely to integrate Polygon network transactions natively on their main retail platform.  Many assumed this would happen when they added Polygon support to the Coinbase Wallet app.  Things could change or this may not get implemented like I assume, but it should mean that eventually moving from Polygon wrapped coins all the way to fiat via Coinbase may get easier and cheaper.

https://blocktelegraph.io/polygon-first-scaling-solution-for-coinbase/