如何了解「喜欢你，我也是」里写这个替代“秒怂”的词？
I know you're not going to be happy with this, but I'm going to write up an answer in English. First, at least.

First about digitization:
Amazon has the same problem you do. They don't know how to render the character. I haven't looked into it very deeply but it looks like they have issues with CJKV extensions. (Perhaps CJK Ext. A is more doable, but I'm not sure about B-G.)
 (⿸尸从) is a CJK Ext. C character.
CJK Ext. characters usually need special font support and that clearly hasn't been implemented into Amazon or Kindle products.

 can be found in Mandarin dictionaries:
Pleco

weak and incompetent

Oxford

weak by nature

CC-CEDICT

weak and incompetent

Perhaps the most well known word with this character is: 包.

For the sake of understanding you can consider 秒 two &quot;words,&quot; instead of one single word.
MDBG

秒
(coll.) instantly

&quot;秒 + verb&quot; has become a trend in neologisms. There are quite a few of these combinations, think: 秒懂，秒回，秒赞，秒睡，秒删, etc. 秒 is a combination of &quot;instant&quot; + &quot;cower.&quot;