Various fixes to ensure robustness of size initialization

[philippjfr]

We noticed some instable initialization in certain scenarios (usually server deployments with some latency). This PR aims to increase robustness.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 87.12%. Comparing base (5f47970) to head (43486a6).
⚠️ Report is 3 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main      #24   +/-   ##
=======================================
  Coverage   87.12%   87.12%           
=======================================
  Files           3        3           
  Lines         101      101           
=======================================
  Hits           88       88           
  Misses         13       13           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.