Your question is a little broad. Not sure if you are asking about camera options or post production hardware/software.
With budget in mind I would recommend a desktop with at least an i7 8 GB ram and a dedicated graphics card. If mobility is required a laptop is better but you get a little less for your money. From a software perspective, there are many options but I would go with a stand alone Premiere Elements license, these are good value in my opinion and they are on sale often. Nowadays I use the adobe cloud suite of apps for personal projects and YouTube production, I love these but it is on the expensive side. Once again, this is just my preference there are a lot of products out there to look at.
In regards to camera options, using your cellphone is always the best bang for your buck and smartphone video capabilities are great nowadays. I do see you do fitness videos, if you wanted to improve video quality or just improve your production process I would look at a good quality camcorder. For example, I have a Sony FDR-AX53 that is so easy to use and shoots very good quality 4k. Considering it is a prosumer level camera, it does not shoot raw and it doesn't offer a fully manual mode but it is a great option for longer, educational type of videos.
