Yeah, if your server maxed out at 256 system threads you didn't have to worry about the fact that 1024 simultaneous calls would crash your DB. But now you're not limited by system threads
You can still use connection pool + platform threads. Or executor with virtual threads and semaphores or blocking queues. It’s mostly a concern for someone who implements a connection pool, for most devs it’s gonna be the same config option of max connection, that you need to pay attention to.
Any modern web app already has multiple instances of the app querying a db, so you have to keep a tally of total connection number either way.