Simple problems have simple solutions:

Allow streamers to set their own subscription amount. Split that amount 50/50. Convert to the country of the stream origin.

If I stream in the United States and somebody subscribes for $5 USD, that's $5 USD that should be split 50/50.

If I take a trip to Germany and [do a stream from there where] somebody subscribes for €5 EUR, That's €5 EUR that should be split 50/50.

When I get back to the USA, I can convert those EUR to USD or leave them as EUR just like any other normal human.

Why is everything forced to be in USD?

One could argue that by forcing payout in USD, it is effectively a money laundering mechanism that bypasses currency export laws of the origin country from the sub to the destination country of the streamer.

Edit: [example clarification]

Your post raises some valid concerns regarding the fairness and transparency of Twitch's subscription model for both viewers and content creators. Here's a breakdown of the issues and some possible solutions:

Issues:
Currency Discrepancies:

Viewers in Europe, the UK, and other regions pay more for subscriptions compared to those in the US, some of them may even find a way to get money from services that people found via articles like this https://www.linkedin.com/pulse/ways-get-2000-your-pocket-today-heres-how-quickly-ashly-flowers-rdgee .
Despite the higher cost in local currencies, content creators receive their revenue share based on a $5 USD subscription.
Creator Payouts:

Streamers outside the US effectively earn less than 50% of the subscription cost due to these currency differences.
Potential Solutions:
Option to Choose Payment Currency:

Allowing viewers to select the currency they pay in could provide more transparency and fairness. This would ensure that the amount paid is consistent and comparable across different regions.
Reasonable Currency Conversion:

Implementing a fair and consistent conversion rate that aligns closely with $5 USD could mitigate the discrepancy. This approach would ensure that viewers are not overcharged and that the conversion rates reflect real-world currency values.
Adjusted Payouts Based on Actual Payments:

Ensuring that content creators receive the appropriate percentage of the actual amount paid by viewers in their local currencies. For instance, if a viewer in the UK pays £5, the creator should receive 50% of that amount, not just the equivalent of 50% of $5 USD.

Its for all payments... i get 100.000 bit Cheer last weeks. The viewer pay 1.506,76 € for this action. And the Streamer earns 1000 US Dollar. What the fxxx is going on here?
Why i get paid in US Dollar in germany if my viewers pay all Subs and cheers in Euro?
Same with the subscribtions. 4 € pay in Germany for a Tier 1 sub, earning 1,81 US Dollar.
Fair is different. That isn't fair from Twitch what they do.

I subscribed to a channel and the subscription did not go through, but the payment is debited. It was paid for by Pix.

SINCE MY LAST PAYOUT I RECEIVED 36 GIFTED SUBS AND MY EARNING ARE LESS THEN $9 FOR ALL 36

I agree with this and have told all my Australian viewers not to subscribe and to cheer with bits instead. It's still a rip off but not as bad as the terrible sub pricing. An Australian viewer purchased a $7.99 gift sub for someone today and I received an all time low of $2.72. I also won't be subbing or gift subbing to channels anymore until they fix the pricing.

This so much!

I am in the UK and not only is the 50/50 cut much too much, but the fees on top and currency conversions make it so we get almost nothing.

my friend didn't get the Subtember discount and half of 8.99 is precisely 4.50 from 3 subs I got $6.56 how? da sack and for my first sub I literally got 1.56 how does that work? like da sack? please fix this or provide a reasonable explanation.

Same in Australia ($8.99 per sub) but I know 50% of that ISN'T going to the streamer and instead Twitch is pocketing the difference. This stops me supporting the streamers I watch why would I ever get a sub of my own let alone gift subs when I'm being charged almost 40% more than someone in the US and none of that extra 40% goes to the streamer? And Twitch wonders why people block ads when they treat both subs and streamers like this.

I agree . . .

Also agree, mark up in GBP is ridiculous!

I agree. Not only is it unfair to both the streamer and the viewers, it also feels dishonest and greedy. If it's $5 in US, make it 4 Euros for the Europeans.

I don't get paid a different rate for each hour i work, I don't see why there should be differing rates in subscriptions depending on where you are and this money paid should definitely not differ from person to person or in amount paid to the streamer. All should be fair in streamer perspective.

I agree.

Paying nearly $8 a sub is crazy....

COULDNT AGREE MORE!