You don't actually need a heavy bag to get better kicks, especially at six months in. Focus on shadowboxing with heavy resistance bands around your legs - loop them around a sturdy anchor point or have someone hold them while you throw kicks. This forces your muscles to work harder and builds real power without needing equipment. Resistance band work also teaches better control since you can't just rely on momentum like you do with a bag. Throw in some basic bodyweight stuff too: lots of leg raises, side-lying leg lifts, and pistol squats if you can manage them. Even doing regular running helps more than people think - been doing morning runs myself for years and the leg endurance translates directly to your kicking power.
The technique side is honestly easier to work on without a bag. Practice in front of a mirror or film yourself so you can actually see what your form looks like. Work on balance drills like standing on one leg while throwing kicks, hold the position for a second, then come back down slowly. This builds stability and forces you to use your core more, which is where real kicking power comes from anyway. If you've got any kind of post, fence, or pull-up bar at home, use it for balance while drilling kicks. Partner drills are gold too - have someone hold mitts or even just their hands up as targets so you're working with resistance and feedback instead of just air.
Your gym situation sucks, but you're probably stronger than you realize right now. Mix the resistance band work with controlled shadowboxing, add in some leg conditioning, and spend time on technique refinement. You'll actually see faster improvement than just hammering a bag for the same amount of time.