I made a post about my Cold Card quitting on me (replacement on the way), and when it quit working I decided to import my wallet into my older Tangem wallet that I wasn't using anymore. I'm not sure why I did this as I didn't need immediate access to my BTC, I think I just paniced at the thought of not having access to it for the moment? Who knows. Anyways, in order to restore my wallet created on the Cold Card, I of course had to enter my seed phrase into Tangem. That's pretty straight forward and standard for any wallet's recovery process, I know. But what I'm being paranoid about is that Tangem is a phone app. So up until this point I've been completely air gapped with my Cold Card Q, and now I'm not. BitDefender Mobile runs on my phone and I don't do anything crazy with it, but how bad of an idea was it to restore my wallet into Tangem? I'm 100% certain it's the legit Tangem App software, so I'm not worried about some of the fake Trezor Suite desktop software horror stories I've read. Am I being too paranoid here or should I just generate a new seed phrase when my new Cold Card Q arrives? I've never put my seed into any digital form/media(photo, text file, etc, etc). I've got 2 paper backups, and a metal seedplate backup (Keystone Tablet Plus), so the ONLY time it's ever seen something "electronic" was when I restored it inside the Tangem app. What are your guys thoughts?
I think that you were paranoid but that's normal because we humans want to get access ASAP to what we lost. In reality, you haven't lose anything but you wanted to see yourself in live that your wallet really holds some coins. If I were you, I would wait for the replacement to arrive and import my keys into a new wallet. But in this case, if I really wanted to see if my coins are back in place, I would use a computer instead of smartphone. I would install Tails on USB flash drive, import keys in tails and once I see that everything is alright, I would remove the stick and shut down my computer.
If you want to do something like this, you should at least use a software that is (1) open source (2) popular/reviewed (3) trustworthy. The wallet you named (Tangem) may be* open source but it is neither popular enough to be reviewed or trustworthy to be used.
This is a good advice, that's why I only use Electrum on my smartphone.
BitDefender Mobile runs on my phone and I don't do anything crazy with it
Somewhat off-topic, but IMO it's worth to remind that you need to trust them (since those antivirus ask lots of permission) and may drain your battery faster.
This is a good advice as well. If I were you, I wouldn't use any antivirus because they are spywares themselves. Also, use your smartphone like a stoic and you won't face problems of needing antivirus.