How can I fix this?
I took this community as an example, but there is the same problem with my site.
You have to use shorter name. That is too long. So, it is unsolveable until devices allow two line descriptions (that would break those layout).
But sure, I can be wrong too. But I’m not 
「いいね！」 1
I think the name is too long
「いいね！」 2
Can I make a short name for the application separately, and leave the full name for the site? (i.e. in the name of the tab, in the links displayed, etc.)
I think the PWA name depends on the short_title site setting
「いいね！」 2