I just upgraded to 2020 from 2018. The Places feature is very slow. It takes between 1-2 minutes to fill the map screen and populate the photos. Here's a screen shot. I presume the program has to download the mapbox feature, but the real delay appears to be in populating the pics. I've turned off media analysis and face recognition and that has improved performance a bit. I'm on the latest WIN10 with 8GB RAM. I didn't use the Places feature much in 2018, so this is a bit of a disappointment.
Hmmm! I just recently installed PSE 2020 on my Desktop and laptop PCs. I had not tried the places feature yet but when I saw your post, I thought I'd better check it out.
I do NOT have a performance problem with the Places map population! I am also using Win 10, but I've got 32 GB mem in both PCs. It only takes a second or two to populate the map. And, I've NOT disabled any features like media analysis and face recognition (except for videos). I also only have about 8,000 photos in my catalog and many of them do not have geolocation data.