I had similar requirements as you and since there was no way to fit them in Obsidian I wrote a plugin for it. This plugin allows you to embed individual PDF pages or even extracts from them in a note. I use it with the concept of source notes as bridge between pdf and my Obsidian notes.
A Bridge Note could look linke this:
Link: [[Fuhren in die postagile Zukunft.pdf#page=110]]
Topics: [[Führung]]
Type: #literatur #schaubild
{
"url" : [[Fuhren in die postagile Zukunft.pdf]],
"page": 110,
"scale" : 1.5,
"rect": [40,355,270,400]
}
Take a look at the Better PDF plugin.