europe cellular data service not working

I see this post is a year old, but the issue continues.

I wonder if turning off the international block worked. It didn't for me.  I had (still do) the same issue.  I was all excited for my next trip thinking all would be good.  Didn't make any difference.  I get a "Welcome to X Country" text so the phone knows I'm there.  Sometimes everything works for a couple of hours and quits.  Sometimes it only works when I'm on wifi.  Interestingly my Galaxy 9 works better than the 20.  Trying to decide which to change: do I get an iPhone (not a fan) or change cell provider.  There is obviously a compatibility issue of some sorts between Samsung and T-Mobile.  As an aside I never had an issue in Europe when I was on Sprint.  Only started happening when everything switched to T-Mobile