I don't have the game to test on it, but this site shows framerates for StarCraft 2 on a UHD 620, which is a step below the 630 used in the 2018 mini. So it depends on your monitor resolution.
You'll need to specify your criteria here. I used to play SC2 semi-competitively on low settings @ 2560x1440 on my 2014 Mini, which has a much slower GPU. It was even passably playable on my 2009 iMac with the lowest settings, but definitely not ideal.
Keep your resolution reasonable and it should work just fine. Use Bootcamp for the best results.
I don't have the game to test on it, but this site shows framerates for StarCraft 2 on a UHD 620, which is a step below the 630 used in the 2018 mini. So it depends on your monitor resolution.