I guess the simplest way would be via Binance, if you have access to it and you go through KYC. I'm not sure if you can buy HIVE directly with fiat on Binance, but you can buy BTC or stablecoins, whatever we have pairs with on Binance.
Since I haven't updated my KYC on Binance, I looked for alternative ways to do it.
One way is through Crypto.com. It has the advantage of topping up a debit card which has some benefits (depending on your tier), but to get from Hive to crypto.com you need to go through another ecosystem like BSC or use SPS which is listed there. In both cases I assume there are some hefty fees, but I haven't gone through this process yet, so I haven't checked them.
One additional way I found today was from MEXC (without KYC) to a Revolut card (via USDT). The fees seem relatively low.