Would I be better off getting a 2018 or 2019 MacBook or a 2018 or 2019 iMac

It really comes down to what you plan on using it for. If you plan on using it a lot more often while you're not home then I think the MacBook is a great choice. If you plan on using it in the comfort of your home then the iMac is a great option. Obviously there are pros and cons to each device respectively, so it really just comes down to which one you feel like you would benefit more from and which one seems more practical.

Honestly I own both devices and for video editing, photo editing, etc. I find the iMac a lot more "natural" because of the larger display and it is easier to use the keyboard and mouse. With the MacBook it is difficult using the trackpad and keyboard because it feels so cluttered, of course you could get an external keyboard and mouse for a MacBook, but considering you'll be on the go it really doesn't make sense to haul all that stuff around. I hope this was somewhat helpful.

It's also worth considering the long-term value of investing in the Apple Silicon family of processors. The newer Mac models with Apple Silicon (M1, M1 Pro, M1 Max, and beyond) offer significant improvements in performance and energy efficiency over their Intel counterparts. Although they might be a bit more expensive, they are likely to provide better longevity and support in the long run, making them a worthwhile investment, especially for demanding tasks like video editing.

Your question comes up often and the answer is ALWAYS the same. It always comes down to the portability, if you want/need it, whether you do or not is 100% up to you. Also, please only buy a 2021 or later or either solution. And also ONLY buy directly from Apple, do not buy used Macs from:

EBay

Craigslist

Nxt door

Local computer shop

your best friend etc.

if you cannot afford a new one ONLY buy an Apple Refurbished Mac from Apple or from a trusted reseller like Macsales.com!!!!! Anywhere else and well best of luck to you!