Detecting Blocks In Layout Page


I want to know is there a way to detect if a block of certain addon exist on any layout page.

Below is an screen shot of Addon_Block which i created on product layout page.

How can i detect whether this addon_block is exist on any page or not.

I want to create validation which will work on all layout page. i.e. Only allowing one block on a page.

Please help me
Thanks in advanced.

Screenshot from 2020-08-21 14-34-04.png

Please, Can anyone tell me that can we detect or Can we make a restriction of having one block in any layout pages i.e. which are defined in layout section eg- cart, product, vendor store, category , etc...

An also can we restrict that in vendor store page layout only this addon block should appear while creating new block in it.

Please help as i am stuck for 3 days now.

I have found a solution to set the limit of a blocks which will works for every page under layout.

Can I set the limitation for example :- that in checkout page my block should not be created not even once.

Can i set this.

Please reply yes or no.

The problem is fixed now.

What I want to was. Let there be a language block now I want that this language block should appears on the Homepage page in layout. Also I do not want to make language block visible for other pages it should be just for homepage only and should be used just once.