Still in the same system and network I assume. If you are an "irrelevant" target let's say, one where there are no stakes in getting to you, this is good enough. Otherwise it's a matter of getting into your UEFI or disk firmware (since both disk share the same system), or rest of the network (router, IoT crap, another system, etc.) and the fact that you have an encrypted disk won't matter that much.

It's about how important a target you are. You only have to make one mistake, and "they" only have to get it right once. There's no defense that you can put up against a team of dedicated hackers with nation state backing unless you are either not on their radar, or have nothing inherently hackable in your life.

A dedicated team? Of course not.

But it's still worthwhile to protect oneself from being an easy target for a system which just scoops anything interesting off the disk it's installed on.