You are quite vocal about this concern. If the 0.5% FX is 50 times higher than a £20 commission (both ways I guess), I believe the trade you are talking about is £200,000 in one transaction (e.g. buy at £80,000 and sell at £120,000).
If these are your figures, you might be better off with another broker, Barclays or HL if there is no FX charge maybe?
Freetrade have made it clear numerous times that they are not running after people with £1m portfolios, they are here to allow entry into investing with a £1. With that amount 0.5% charge is negligible, nor it is with £1,000.
0.5% also does not concern consumers as much as a huge flat fee that makes investing unreasonable without £20,000 to start with. And if people amass such a portfolio, Freetrade will not hold them in chains, they will be free to transfer to any other broker they wish. In your case, you might even be better off remaining with your current provider given your negativity about the pricing schedule - at least it is concise and transparent, everyone will be able to make decisions for themselves.
Although it seems like you are quite unhappy with the service your broker provides, which is why you devote your time opening our eyes on this “issue”. Because if you were, you could have more interesting things to discuss.