i did boxing and kickboxing aswell and i can tell you, that it is hard to mix both. I don't really know your current fitness level but if you are not intermediate or at an advanced level i can tell you that it is going to be very hard.
I don't know about your boxing training so i guess it is like mine.
A lot of Cardio, technic and strength.
We did a lot of Push Ups and Leg exercises in my boxing lesson, ah i have to come to my point.
The Motivation and time to recover:
I was really motivated in the beginning. Yeah 2 times the week kickboxing and 3 days extra Calisthenic. "Give me 3 month I am a new Legend". No way brother. 3 week, maybe 4, than "My journey" was over.. It is hard to do well in your Box workout when you suffer from Calisthenic Workout. There were days I coulnd't workout really well because i had a lot of soreness from the kickboxing lessons. I had very short workouts, skipped the last exercises, bad form etc. On other days I had both, first Calisthenic Workout and after that directly kickboxing. Same result, i wasn't fresh enough. I lost my motivation. 1 Week break, than two. bam a month withouth any kind of workout.
But hell no, i don't want to fear you, maybe you can do both, maybe not.
You have to find your right way, but don't underestimate it. You still need enough time for recovering.
Maybe you can work like this:
2 Days Boxing, 2 Days Calisthenic, 3 Days Rest.
If it works good maybe an extra Calisthenic Day, but it is hard.
If it does not work, skip one boxing day. Or one Cali? I don't know your main goal, find it!
And if you have the feeling that your body needs a rest, give your body time to recover.
I hope i can help with my answer. Keep motivated. I am looking forward to hear from you? Please write a feedback about your training weeks!
And when it is to hard in the moment, no shame. It all comes step by step.