If your site is aimed at the domestic market or Asian countries, it is better to choose a data center in Ukraine. If the target audience is from CIS countries, then Ukraine or Poland will be suitable.
If most of the visitors are from Europe, the Netherlands is a good location.
For users from Canada, the United States, or Mexico, the site hosted in America will load fast.
Choosing a data center location is free and does not affect the cost of the Magento hosting.