I'm having trouble with preview environments (not PR previews)

I’m not seeing any feedback, so I’m kind of assuming they don’t work. I am using GitLab. I have supplied a credit card. On master I have my render.yaml:

previewsEnabled: true
previewsExpireAfterDays: 3

  # back
  - type: web
    name: test-back
    env: docker
    region: oregon
    plan: starter
    dockerfilePath: ./back/Dockerfile
    dockerContext: .
    healthCheckPath: /health
    initialDeployHook: node scripts/migrate.mjs && node scripts/seed.mjs
          name: test-db
          property: connectionString
      minInstances: 1
      maxInstances: 5
      targetMemoryPercent: 60
      targetCPUPercent: 60

  # front
  - type: web
    name: test-front
    env: static
    buildCommand: ./front/scripts/build
    staticPublishPath: ./front/dist/www

  - name: test-db
    postgresMajorVersion: 13
    region: oregon
    plan: starter
    previewPlan: starter

Should I be seeing something pop up on MRs? Or in the PRs tab in the render UI? Do I need to turn pullRequestPreviewsEnabled: true on specific services? Does this just not work with Gitlab?

It appears that I just didn’t wait long enough. The PR tab in a service does not get a link, but instead you can find the separate cluster of stuff in the yaml page. It seems like they don’t stay quite as up-to-date as PR previews (you can go in and manual deploy the latest commit, if it isn’t picking it up).