Before the size of text is normal, now it displays text in very small size.

I checked the setting, Font size = Large.

That happened to me too.I use ithe screen as a flashlight and often enough a chance knock in the dark brings it to settings and I get either  high contrast or ,like you small font that I cannot seem to change.

I have just lived with it  for the past few weeks as I cannot find the way back

May have changed Accessibility setting for Vision(font and screen zoom).

18 minutes ago, Endy0816 said:

May have changed Accessibility setting for Vision(font and screen zoom).

No ,don't think it is that ,for me (I just zoom it up to what is comfortable now .These devices can be frustrating but never so bad as to wreak physical vengeance on them- in my case the user is equally to "blame")

Could be due to the resolution setting too.

Edited September 11, 20214 yr by Endy0816

6 minutes ago, Endy0816 said:

Might be due to Resolution. I'm seeing a setting under Performance Mode and Display for that one.

I spoke too soon .I think your first idea may have changed my settings back to  more or less how it was(though what I actually did I am not quite sure ,since it didn't seem to work the last time I tried)

In different versions of Android you change it slightly differently. In my I simply type "font" (the local language equivalent).

Font sizes are stored in sp units (scalable pixels). Other elements dimensions and borders are in dp units (density-independent pixels).

https://developer.android.com/training/multiscreen/screendensities

 

4 hours ago, PeterBushMan said:

I checked the setting, Font size = Large.

Adjust it to Small. Restart device. Adjust back to Large. Maybe what is displayed in UI was no stored in config files. It can happen if application's activity is delaying saving settings to onPause/onStop/onDestroy, but sometimes Android OS don't execute these methods (especially in out of memory situations, or when app is terminated due to crash, i.e. when app is unexpectedly shutdown)

Edited September 11, 20214 yr by Sensei