You can always swap storj coins to USDC or USDT and bridge them to any other network — e.g. polygon.
The right way may be not to :). Even though there are some exchanges that support L2 to fiat, conversion to currency is expensive and unnecessary.
I personally convert storj tokens to Usdt, send them to bitrefill, and buy gift cards for the services I use (Apple iCloud, Amazon, AT&T wireless, even prepaid debit cards, etc). I’m sure there are similar services in EU (Binance?)
This way you are avoiding almost all fees, and L2 fees are negligible - a far cry from L1 gas fees. Another bonus — you avoid KYC hassles.
Here is the recent discussion on the topic with the link to a larger thread: How to enjoy funds from zkSync - #3 by arrogantrabbit