Suggestion: Try Minecraft: Educatiion Edition (you may have to work with your IT/network people for firewall, install, etc.)
https://education.minecraft.ne...
If you want to go more 2D graphics, CMU CS Academy (Carnegie Mellon U) has some free browser based tools/programs for Python programming with graphics, a lot like Processing if you're familiar with it. I customize most of the lessons though, as it can be a bit basic/repetitive, but it has a sandbox that you can play with
https://academy.cs.cmu.edu/cou...
I've used MC:EE with a lot of success with 8th graders for one semester elective, lots of engagement. It utilizes MakeCode which supports, block, JavaScript and Python. The students, even the 'non-coder' ones, love it -- a simple loop to spawn creatures, or using the Agent to build a structure with nested loops is a more engaging that a lot of traditional lessons. By the end of my class, the kids learn all the core stuff (variable, lists, loops, control-flow, some OOP basics, writing their own functions with parameters, etc.) that you're probably aiming for. Not sure of your age levels, but there's enough complexity available that if you have older kids you can definitely adapt it to more challenging projects.
Yes, it's gamification, but that's not always a negative. I use that class as a feeder into our more advanced stuff for high school, and the vast majority of kids who do the MineCraft stuff enroll in our high school classes.
Honestly, it's also a lot of fun to teach with, I mean, it's MineCraft... :)
I've been teaching for 8+ years, it's not easy so I know jumping into it is a challenge, but stick with it -- focus on the fun, do a lot of project-based learning, and give the kids so more control over the projects they work on, they will be more involved if that have more agency.