meta_query results not the same with and without spaces

The problem is that you’re comparing 10000 and 10 000 as strings, and as such they are not the same value.

So, you either need to sanitize the strings to ensure that both return an equivalent value, or you’ll need to force them to be integers, so that they’ll be evaluated as the same value.

Edit

Your best solution is probably to replace your text form field with a select, that includes pre-determined entry values (e.g. 10,000, 20,000, 30,000, etc.). That way, you will have reliable data to use in your meta_query.