Multiple filters based on one filter

Hey, I have a following case. We have a project, where there are workers and finders. Each worker puts in expected salary in currency of their choice (let’s say it’s USD, GBP, EUR, PLN for now). Finders that search for the workers can choose currency in which they search.
Simple example: Let’s say 0.5 EUR = 1 USD. Worker A puts in their expected salary of 10000 USD monthly. So if finder is looking for worker 5000 EUR, he should see worker A. But as we know currencies’ rates change overtime. So if becomes 1 EUR = 1 USD, then this finder shouldn’t be able to see that worker.

I found two ways to handle this:

  1. Update all records in DB and algolia with some CRON job (I really don’t want to this :<)
  2. Get currencies rates, multiply it and do OR query for available currencies.

So regarding 2nd way, how do I do it with frontend? Let’s say user chose EUR checkbox and put in some number. So the query should be something like:
(input and currency === "eur") OR (input * gbpRate AND currency === "gbp") OR (input * usdRate AND currency === "usd") OR (input * plnRate AND currency === "pln").
Is there a way to do this frontend side or can I do it some other way?