A friend of mine said that he found looking for streamers on Twitch that stream something you're interested in with your target language. Cos they most likely have a discord server, and it gives you the opportunity to converse with their community, and you'll often be welcomed and helped out.
Also Polish discord servers are a good place to start. From top of my head I know streamer ones like JacexDowozWideo or ARHN.EU which both should be welcoming, and even though we're on lemmy I know that the subreddit r/polska also has a discord server as well, so it should be a nice place to start.
I don't know how active the polish community on it is in your area, but there's an app called Amikumu that exists to help connect people with people that speak the languages they are learning.
Depending on where you live, if theres a decent sized polish populationo you can also ask around at polish social clubs, churches, bars/restaurants, etc. Odds are that someone there either speaks at least some polish or knows someone who does.
Not sure if this is a universal concept but most larger cities around here have 'language cafes', both for learning the native tongue and for practicing a new language
I haven’t looked at polish specifically, but I’ve had success with practicing languages on discord servers for language. If you check disboard for language servers, the large ones have plenty of people who want to practice