kio gdrive in gtk apps

I’m guessing the answer is “no”, but I’m gonna try asking anyway.
Is there a way to make gtk apps such as Thunderbird and Chrome kio-gdrive aware?
e.g. If I want to save a pdf file to gdrive that I have opened up in Chrome - gdrive does not appear in the save file dialogue. To get that I need to open the pdf file in okular and save it from there (or save locally then use dolphin to transfer to gdrive).

Just surmising here, so could well be wrong…I assume Thunderbird and Chrome launch nautilus (Gnome Files) as the file manager?

This might offer a means to an end?

Apologies if on the wrong track here. (I don’t use Google Drive at all.)

actually, chrome does allow me to save to gdrive

but Thunderbird does not have a remote option in places

What happens if you right-click on the the left panel? Nothing hidden?