Juniors should be expected not to know things and to make potentially deadly mistakes, and it's the job of a senior to take on the additional responsibility of

Juniors should be expected not to know things and to make potentially deadly mistakes, and it's the job of a senior to take on the additional responsibility of being their "shadow", making sure the path they're asking them to go down is safe and correct their course if they stray from it, all while explaining all the whys and why nots. If you're being given tasks nobody knows what to do, your mistakes make it further down the line than they should have, and to be fair if you have enough room to go far down the wrong route and commit to a mistake, a senior developer on your team is not doing their job properly. I'd say talk to them and tell them you need a bit more oversight because everyone will be better off that way - you're entitled to it as a junior dev after all. If they don't cooperate, just get out of there and find a better team because KNOWINGLY overloading juniors with difficult unsupervised work just sounds like exploitation