Why is desktop more secure

Hello,

I'm new to crypto and currently have a small amount of BTC on Mycelium on my Android device. I ran a virus and malware scan on the phone prior to installing the wallet.

I'm considering also looking into some alt coins, and that led me to looking at Exodus for a desktop wallet.

My gut would tell me a mobile wallet is more secure than a desktop wallet like Exodus, since its exposure to the internet is more limited, as I'm using my PC for more things and being more "exposed".

I know a mobile wallet can be lost or stolen, however, since I have the 12 word seed phrase, it seems more secure than a Desktop wallet where you could get a keylogger or other virus and have your private key stolen.

However, many sites online say the opposite that Desktop is more secure?

Im trying to decide if I should move my funds to Exodus and operate all in 1 program, ( I wanna dip into alt coins as well), or if Mycelium is a more secure option.

I'll be looking into a hardware wallet for cold storage when I more funds invested in Crypto.

Thanks.