So this is my opinion.
1st: What setup do you have now? How long realistically do you plan on keeping it if you buy a drone instead.
2nd: Obliviously knowing what your doing and how to shoot is top priority.
That being said the next most important thing with shooting isn't your camera it's the lenses (Glass). If you buy an expensive camera and have crappy lenses it's not going to be a great result. I've learned this as I had a DSLR and now a sony fs700 with decent lenses and the quality was always just par.
I bought another camera (fs700) then put money into nice glass and that has made a huge difference.
The camera I bought wasn't the difference. At first I had to use crappy lenses because I couldn't afford nice glass after buying the fs700 and the result was still just ok. Now having one really good lens made a huge difference.
Also investing in glass is much smarter than cameras, as cameras are always being updated etc. Lenses hold value
3rd: What I would recommend is figuring out what camera you will be using for a solid period of time. So if your thinking of upgrading and buying a camera in the next 2 years I would do that now.
When looking at a camera think of wants and needs. What you need and what you want. Depending on budget you may have to make some sacrifices. You need to be realistic if you need the newest/ highest end camera. Also buy used, you will save an incredible amount of money. Lots of people with cameras that are upgrading there setup, will sell there old setup. Their old setup there selling can be an upgrade for you.
Then figure the brand like canon, nikon, sony. So you don't have to switch over, at least not for a bit. Plan on having this setup for a solid period of time.
What you need to figure out is if your going to stay with the censor size and brand of your camera.
Don't invest in nikon lenses if you later might buy a canon camera. Also don't invest in crop lenses if your gonna switch to full frame.
Then figure out what you want/need as far as the specific camera. Photo vs Video. Then crop censor vs Full frame etc.
Once you have this all figured out and come to conclusion for a camera you can look at glass.
This way you don't end up investing in nice glass that's for Nikon and then having to sell it cause you switch to sony etc.
Same with investing in glass for crop sensor and switching to full frame etc.
Spark Notes: If you plan on keeping your current setup for at least 2 years then you have 2 options. This opinion and options are based on you keeping your current setup.
1.) Either look at upgrading your glass and accessories. If you already have nice glass over a variety of focal lengths then you might be all set. Then accessories, think if you need a good tripod or glidecam etc. If you have this covered as well then go to option 2.
2.) Buy the drone. So many people buy drones and have no clue what there doing and there complete jerry's. I see so many of these on craigslist as some retired guy buys one then realizes he hates it. You can haggle with people like this and save a ton of money. They just want to get rid of it. Obviously you will have to research which one you want/need. Then you can check the condition in person to make sure everything is good if you buy one used. Everything works/ functions properly.
Just understand you can't just buy a drone and use it all the time and expect people will be hyped. Meaning: A drone is a tool like a camera, lens tripod etc. If you have a million drone shots it get's boring and played out just like an edit with only follow cams, only long lens shots etc. You don't want to be static in film making. Switch up focal lenghts, drone shots etc.
A Perfect example is Ian Avery Leaf and his work. He has drone shots, follow cam shots, Long lens tripod shots etc, all in one edit. So it's a perfect variety and blend. You never get bored as it's visually appealing.
So don't think you can buy a drone use it all the time and everything will turn to gold. Film making needs to flow, be an assortment and changing throughout the work. So making everything blend and not choppy will make the film or composition be fluid. If you have a bunch of drone shots it gets boring. Just like if you have a bunch of photos you took that are all wide angle. When you view a nice portfolio there's a strong variety.