Random volunteers. That’s a lot different than actual military personnel being involved in the conflict. As far as I know the most that has been done officially is to provide strategic advisors and training the ukrainian troops in the use of the more complex equipment provided.

only volunteers

There's been a lot of Poles fighting in Ukraine, but not officially. Hard to say how much Polish government has been organising it, but while it has been on less level than let's say Italian blackshirts in Spain, some effort clearly been made since this is technically mercenary work which is illegal in Poland, and yet there was no or barely any arrests because of that, meaning police was ordered to look the other way when those people coming back.