BEM - repeating blocks and elements, what about duplicating properties?

Question

BEM

I'm still tormented by one single question, the meaning of BAM is clear.
According to the principle, an element cannot be outside the block, the question is, but if I have similar properties, then according to this logic, do I need to duplicate the properties?
That is, I have

block {}
 block__btn {}
 block_text {}

block1 {}
 block1__btn {}
 block1__text {}

what if my properties are the same?
Duplicate everything?
In fact, even such an entry block__btn{}, block1__btn {}
will not work, since block1 may change later.
The very essence of the question is even more, in the html hierarchy, according to the logic of bam, I can’t have such a structure if the elements are the same in properties, but in different blocks.

<div class="block">
 <div class="block__btn"></div>
 <div class="block__text"></div>
</div>

<div class="block1">
 <div class="block1__btn"></div>
 <div class="block__text"></div>
</div>

Only the answer, please, in Russian words and without a direction to Google, I already read it there.

Answer 1

I'm still tormented by one single question, the meaning of BAM is clear.

Clearly understood? The point is to avoid duplicates.

if the elements have the same properties, but in different blocks.

Then from these elements you need to make a block, it will be something like this:

<div class="block">
 <div class="btn block__btn"></div>
 <div class="text block__text"></div>
</div>

<div class="block1">
 <div class="btn block1__btn"></div>
 <div class="text block1__text"></div>
</div>

Answer 2

In fact, even such an entry block__btn{}, block1__btn {}
will not work, since block1 may change later.

block_btn, block1_btn {
color: red;
width: 100%;
}
block1_btn {
width: 80%
}

Answer 3

If I understand you correctly, then the parent needs to add a modifier, and already change some properties in it.

<div class="block">
 <div class="block__btn"></div>
 <div class="block__text"></div>
</div>

<div class="block block--notDefaultBtn">
 <div class="block__btn"></div>
 <div class="block__text"></div>
</div>

Answer 4

In this case, you need to use modifiers
https://en.bem.info/methodology/block-modification/