Don makes a good point about the OS. I think the next iPad Pro will probably be better in that sense though. The iPadOs is new and came out after the current iPadPros. The next iPad pro should be more integrated with the OS.
Don is right about using an iPad Pro with a Mac, especially a Mac that runs the latest OS, and using the iPad Pro as a second monitor. This would be the ideal way to use the iPad Pro because you would have the power of a Mac with the drawing function of the iPad Pro.
The best way to buy an iPad Pro may be to buy it through ATT, Sprint, Verizon, etc. They offer 24 month payment plans that do not charge interest. You do have to have a phone plan with them though. I haven't seen one, but a plan that let's you lease and upgrade after 1 year, like the phones, would be the best way.
I don't know if tying your iPad to a cellphone company is the best way to go. First of all, you'll spend an additional $130 to get a model with a built-in cellular transmitter for whatever standard your carrier uses. (AT&T and T-Mobile use GSM standard and their Mac phones/tablets are strictly GSM, while Sprint and Verizon are CDMA standard and have models from Apple with both CDMA and GSM hardware in them.)
Buying with monthly payments from the cell carrier usually means you're financing it - paying extra for interest. But even without interest, there's the cost of the data service with those companies - it can add up fast, easily costing more than any interest plan. You can also buy from Apple, perhaps even getting an unlocked model so you can jump carriers, but if you get it on some kind of a monthly plan, you're still paying interest. I know they do leasing for iPhones, but I don't know if they lease iPads - I lease my iPhone because it's costing me less than I was spending in the long run (I like high-end models) and allows me to upgrade my phone annually instead of every two years or more.
If you're not planning to go whole hog on the iPad because you're not planning to use it as a gaming machine or a media library (you can stream your video and music anyway!), you can get a low-memory model pretty inexpensively, even with a big screen - all current iPads (mini, standard, Air and Pro) use the Apple Pencil and are "Sidecar-capable" with MacOS Catalina. The cheapest new model to get would be a standard iPad 32Gb with a 10.2" screen for $329, with a Retina display, support for Smart Keyboard if you wanted it, and an A10 Fusion processor. For $100 extra, you get four times the memory, 128 Gb. A 1st-gen Apple Pencil to use with it is $99 (only the iPad Pro is compatible with the 2nd-gen model Apple Pencil, which has easier, wireless charging, but there are also third-party models to consider, if one wanted to look around). Using WiFi alone without built-in cellular is just fine - if you have a data plan for your phone, especially if it's an unlimited plan, many such plans come with tethering (using your phone as a WiFi hotspot for a certain amount of data per month, included in the cost of the plan). For example, my Sprint plan has 50 Gb/month of included tethering. An iPad user need not have a built-in cell transmitter to get online on the go. Plus we were talking about using this more as a drawing tablet with a MacBook, less as an on-the-go notebook alternative.
So, for at little as $429, you have a complete iPad-as-drawing-tablet solution for using with any MacBook running MacOS Catalina. And it's not just a drawing tablet - it's also a standalone computing device, a video/still camera, a media player and a second screen for the MacBook. Look for a refurb and you might even save a few bucks, if one's available.