Use Inkscape to export your file to PNG.
Open the PNG in Gimp and export it to a variety of file formats.
Currently, the 2.10 export dialog box does not show the file types dialog. But if you type the correct file extension, you will have the specific dialog box for that file type.
Yes, this is normal.
Practically all royalty-free stock image sites have a clause which prohibits usage as a primary brand identifier (logo). Your usage is described as a logo usage overall, even if you aren't calling it a "logo".
I understand the issue is troubling for you. But I don't know what resolution you are expecting here.
Either purchase ...
Stock image sites can make any rule they want as far a licensing is concerned. It's their business, and their rules. So yes, that's normal. You may have to pay for an extended licence for certain uses. They might not allow certain uses at all. I've come across this before where certain images are not allowed to be used for example as prints or on printed ...
I'm sure you'll find suitable icons of vegetables in about any stock image website like Adobe stock, shutterstock, iStock, pixabay etc.
No affiliation to any of these
Never seen this rule for any stock image and am not sure why they made this rule. The most similar rule I came across is that if an illustration ...