The imported wallet is compromised because of exporting the entire keylist.txt file to the hard disk?
It's not as secure as an encrypted wallet file, but you should be save assuming your PC isn't infected with malware. Since malware is fairly common it is recommended to store larger sums on hardware wallets or using a cold storage setup. If you only store a couple of bucks at a time, are fairly careful when browsing the web and don't run executables from suspicious sources you should be fine. Just make sure you don't share the keylist.txt file on the internet and don't store it on an online drive or similar.
So the funds be transferred to another electrum wallet with a different keylist? How do I do that?
By sweeping the funds in a fresh electrum wallet:
This transfers the funds from the old Armory addresses to your new Electrum wallet which leaves the old Armory addresses empty. Just make sure you write down the Electrum seed words and keep them safe.
Do you think the Electrum address will work with the "Bitcoin Depot" type ATM? With the original failed attempt with Electrum, it is very possible that the address could have been entered incorrectly. On my last deposit with a manually entered address four attempts were required due to being hasty entering in the address. Second attempt to scan the Armory barcode with a laptop was successful at a distance greater than six inches.
Legacy addresses (starting with "1") should definitely work. SegWit addresses (starting with "bc1") may or may not be supported (Couldn't find any info on that). Note that sending bitcoins from legacy addresses requires higher fees than SegWit transactions (but still should usually just be a couple of cents, assuming you don't run into a blockchain rush hour).
The incentive to use a Bitcoin ATM for cash is to have a more private VPN. Certain companies allow you to even mail in cash. Of course any type of cyber currency might be more private than a credit card.
If purchasing bitcoin online how does that differ in terms of privacy from using a Bitcoin Depot ATM?
Exchanges usually require you to send in some documentation as to verify your identity. Assuming you tumble your coins before making any purchases, exchanges and authorities will have little insight on what happens with the coins once they leave the exchange. Note that paying an invoice using BitPay exposes your IP to them (They require wallets to fetch payment information from their servers over clearnet), unless you route all your connections over a VPN (chicken egg problem, anyone?).
"Tumblers" that provide some anonymity, but that takes a certain amount of time?
Most tumblers let you withdraw your coins instantly after 1-3 confirmations, however it is recommended to let at least a couple of hours (or even days) pass for improved privacy.
Some wallets have built-in privacy measures (eg. Wasabi, which can act as an tumbler using coin-joins), however they can be rather slow and unwieldy (so probably not a good idea after your Armory adventure).
LeGaulois has compiled a nice list here:
https://bitcointalksearch.org/topic/2023-list-bitcoin-mixers-bitcoin-tumblers-websites-2827109Be extremely careful that you enter the correct domains, there are plenty of phishing sites about.
The cash ATM is more private, right?
Assuming they don't ask for your passport or biometric data, yes. But you can improve the privacy of exchange-bought coins using the methods mentioned above.
Bitcoin depot told me some people purchase some hardware or "gaming?" things that charge less for Bitcoin because it cannot be charged back.
I assume they refer to mining hardware. Don't bother if you only want to do some occasional spending.