You are correct, you can ‘input’ the ‘mailto’ address.
Ok so specific to my iPhone, lets use the (3) email addresses below:
on my phone I have the iOS default Mail app connected to icloud & work emails and work email is the default
I have my gmail email connected with gmail app
so appears that in all cases any emails from my apps will generate a draft email using the default email address on the native iOS Mail app (my work.com email address)
I can test this by changing the default email address to my icloud email address and see if that changes the address that the draft email is generated with.
so then it appears you cannot control or change the ‘email from’ address within Glide itself.