What I like about them for forex is that they're publicly traded, so I can take a look and see if they're at risk of disappearing anytime soon. And assume they have some good auditing.

https://www.londonstockexchange.com/stock/WISE/wise-plc/comp...

Only takes one horror story to read about a currency exchanger taking your wire and then going bankrupt before wiring you funds back to want to avoid private currency exchangers forever.

My other method in Canada for conversions between US$ and CAD$ is to buy an "inter-listed" stock that trades in both Toronto and New York City. My stock broker will sell me a bank/telecom/whatever in CAD$ in Toronto, and then let me sell it for US$ in NYC. Hedge funds, etc. keep the two stocks in lockstep with exchange rates. Tis called "Norbert's Gambit". Cheaper than Wise (basically $20 flat rate for me and about 0.02% in spread if I take a bit of risk with a real stock).

I suspect this might be possible in Europe if you have access to different markets across the continent.