I still think DS1 is the best place to start if you've never played a Soulslike. It's really your only chance to get the full best impression as coming back to it after playing Elden Ring or something your reaction to most of the bosses will be "... that's it?". If it's your first soulslike they'll feel epic. And it's really not that unapproachable, just tell people to take it slow and use a shield, and ask you for directions if they get stuck somewhere.
I still have yet to play Sekiro, I need to tackle it some day but it honestly intimidates me. Several parts of DS3 and ER already felt like it were pushing against my skill ceiling in a way that was unfun and in Sekiro you can't even cheese or grind or rely on gimmicks. I'm fairly certain I'll not be able to finish it, and I won't enjoy bashing my head against it until I give up and feel like a useless sack of shit.