Solid answers. I haven’t tried Bull Bitcoin but I agree, I’d be hesitant to mail cash (though my understanding is that it used to be a pretty common way to buy 🌽)…
RoboSats (or bisq or hodl hodl) would definitely be worth looking into. Convenient, private, and secure — the bond + escrow function seems to do a good job keeping scammers out. RS uses Lightning which is sweet, although their node was having issues last week so maybe give it a few days before testing, to make sure it’s all resolved.