It was really weird going back to Europe and have my phone on 3g half the time. I just never see that in Japan. It’s either 4/5g or nothing at all.

It's very different on location in Europe. Where I live I have realized we are a bit spoiled. I was biking through the (small) forest outside Bonn in Germany. This used to be the capital during the east germany thing. It was impossible to access internet for the GPS game I'm playing (turfgame.com) so I had to turn off GPS and get back to the road to be able to take the zones. This keeps happening the whole time even driving around on smaller roads.

South sweden this almost never happens, here in north Sweden in can happen that you drop down to 2G and can only do SMS but then you really have to go deep into the forests. Up in the mountains you will lose connection completely though. Especially now when they shut down the older networks that has longer reach.

As sibling post said, it just really depends on the location in Europe. Here in Turin (NW Italy), everything is 4G-LTE/5G and they're phasing out 3G completely.