No Full Site Editor

I have used WP for years, but am new to 5.9 and the block editors. I set up a new site and initially installed the twentytwentytwo theme. Not understanding what I was seeing, switched to aver old theme, coraline. When I switch back the Full Site Editor links are not present. What can I do to get that back? I may still return to coraline, but I want to play with the new features.