Looking for alternative dog door covers (slides?) for an Ideal Pet Ruff Weather, because my size doesn’t seem to exist anymore.

I have a Ruff Weather dog door that seems to be oddly sized, its around 11ish inches wide and 19" tall and I don't see that as an option from their website. Maybe they don't make it anymore? My house is old and I really need to seal the door properly as its killing my heating.

The Ruff Weather doors I see for sale are 9.75" x 17" or 15"x 23.5", which really aren't even close. Are there any door close-ish that have worked for people?

I also am expecting a pretty big winter storm this weekend, so I need to figure out something for the next few days. I was duct taping cardboard over the door frame, but that only lasts a week or so before the tape dries out and starts falling off when its wet.