if my FX math is right (feel free to correct), unless this is some specific currency which got weaker agains the dollar, in general if you converted USD in 2024 and the $ weakened, you should have a gain in USD terms not a loss?
on 1/1/24, 1 USD = 0.90599 EUR
on 7/29/25, 0.90599 EUR = 1.05 USD.
I don't think converting to a different currency and not back to USD creates a gain/loss based on FX rate changing, you just have a different currency.
If you move it back to USD maybe it's a taxable event this is covered by Section 988 of the tax code which has certain exclusions around 'personal' transactions. I've had FX losses in the past on currency conversion from USD and back to USD, which a CPA advised me were not something I could take on my taxes, but I'm not sure if that advice was correct.
If you are looking at significant amounts you may want to consult a CPA on this topic. Try reddit r/tax and r/irs forums also.
