It's much better for rabbits to be indoors rather than outdoors. In my opinion, it's more cruel to house them outdoors in an unsafe area than it is to keep them inside where it's safer.I personally don’t think so either but my mom thinks it’s better to keep them outside because she thinks it’s cruel for them to be kept indoors. Our chicken run is definitely big enough for them but it’s hard because the chickens need to lay eggs and they have food and water in there and their coop is in there. It’s the only secure place we have outdoors therefore my mom keeps them in there.
When housed outdoors, rabbits are vulnerable to predators (which can kill them without even getting close, since rabbits often die of shock), they aren't as well protected for weather (heat can be deadly to them), they often don't have nearly as much space as they should, and they won't be able to bond with you as much.
I recommend keeping them in a large wire dog pen. Cages are much too small, overpriced, cheaply made, and overall are just not worth it. They can't provide room for the basic needs alone, including a large cat sized litter box (they should be able to turn all the way around in it), plenty of hidey houses, food and water dishes (not water bottles because they don't provide enough water, are hard to clean, and are unnatural to drink from), along with plenty of toys. Even if a cage did have room for all those things it wouldn't leave room for play and exercise, especially for two rabbits.
How old are they? Rabbits can reproduce as early as 4 months, or even younger in some cases, so I would separate them as soon as possible until you can get them both fixed at 6 months. After they've been fixed, they need some time for recovery and for their hormones to "calm down".
It's best if both rabbits are fixed so that you can bond them properly. In order for the rabbits to live together in peace, they'll have to go through the bonding process, which could be very quick, or could take months. For this to all work out though they should both be fixed.
Getting them fixed will also help with litter training, and should make them more friendly overall. Once rabbits turn 6 months old they go through a "teenage phase" where they often are territorial, they may mark more, and can even be aggressive. Sadly, this is when many people dump their rabbits. But getting them both fixed will resolve these issues and just spending some time with them and bonding will be helpful.
Lennon the Bunny, 101Rabbits, and the Bunny Lady on YouTube all have great information on rabbit care.