You'll want or need an ssh app, or an RDP/VNC/ARD app, or both. These are available for iPadOS.
Due to the issues around poking connections through firewalls, and due to the latency involved in remote connections, ssh is the local preference. Locally, I use Panic Prompt, and there are other ssh apps around.
If you're in an environment that lacks an ssh server and a command line environment, then you'll be looking for an RDP/VNC/ARD app. Maybe also a VPN connection, as all open RDP/VNC/ARD services will almost inevitably get deluged with login attempts. Forwarding screens around also tends to be awkward, particularly for any apps expecting modern resolutions and refresh rates, or for the sorts of cellular and Wi-Fi network connections with bandwidth and latency issues.
You could conceivably build and load an x86 or x86-64 emulator into your iPad Pro, and then run an operating system as a guest. but you'd need to create and/or scrounge the source code, and use Xcode or the command line tools to build that emulator. And it'd be a fair amount of work to get there, and emulation will be rather battery-intensive. Apple doesn't allow these sorts of configurations in the App Store, so you'll have to rummage to get where you want. One other alternative is—if source code is available—to compile to JavaScript and run the operating system and/or the app in a web browser. Or compile to WASM, if you're inclined.
Emulation tends to be slow.
Apple Developer Program membership is not required for loading code on your own iPad, just for distributing it to macOS or iOS or iPadOS or watchOS via the Apple app stores, or via notarization and related code signing. Xcode has allowed loading code onto iOS and iPadOS locally for a few years without program membership.
Details: https://apps.apple.com/us/app/xcode/id497799835?mt=12
For writing text or code, you'll also want to evaluate whether the iPadOS soft keyboard, a case keyboard such as the Apple keyboard folio, or an external Bluetooth keyboard will be most effective and appropriate for your needs. I'm fairly speedy when typing with the iPadOS soft keyboard, but still faster with a traditional hardware keyboard. And I don't have the soft keyboard occupying that part of the display.
iPad screens are fairly small, too. Even the iPad Pro 12.9" 2018 model. That as compared with the sorts of large screens that various of us are used to programming with. I use iPad for most of what you're doing, but I don't try to program with it. Patches, investigations, troubleshooting, but—for my preferred programming usage—programming really needs a larger display, whether programming using vim, Xcode, or otherwise.
And entirely FWIW, have a look at Dash as a documentation resource, too. There are versions of that for macOS and iOS.
