I've not been affected by screen burn on my phone's however it can certainly affect some phone's which can attributed to how it's used.
My screen time out is set to 2 minutes and it's rare I leave anything static on my screen for extended lengths of time.
Samsung phone's are designed and optimised to utilise widgets so they shouldn't adversely affect your phone.
The Samsung Limited Manufacturing Warranty should cover issues like this.
Current Phone > Samsung Z Fold³ 5G.