Actually, I totally agree with your main idea. But it doesn't sound wise for me to save all the information on a $ 100 device. I guess you didn't follow the latest developments about Electrum wallets. Unfortunately, there are many problems with the Electrum wallet. I have doubts about trusting such devices and apps.
In fact the best option might be the paper wallet. As you said, taking extra security measures for those who have invested a significant amount.
I've had no issues with electrum? The issues were people that fall for phishing scams.... There were connectivity issues but if you're not in a rush to spend, it doesn't matter and if you are you can put your signed transaction into the network with online tools.
There was a json rpc injection thing also which wasn't as bad as I thought and you could get past that with merely a password which you should use anyway.
None of these issues (other than connectivity ones) have faced android electrum as it doesn't show errors anyway in detail...
An sd card can withstand more than paper can...
You have to generate the paper wallet somewhere unless you use dice throws and do it purely mathematical.