What can replace MDT without making task sequences a pain?

DeployR is probably the first one I'd evaluate if the task sequence workflow is what you want to keep. It's similar to MDT, so it may make the transition less jarring than switching to an image-first product.

If PXE is already working for MDT, you may be able to keep the existing network setup and change the boot image. Test the driver selection, naming rules, scripts, and activation against your actual setup before committing.

Take a look at PDQ SmartDeploy. It uses a single image with model-specific driver packages rather than requiring separate images for each hardware model. It supports both on-premises and remote deployment.

I'd check how its deployment workflow handles your scripts and naming convention, and whether its driver library covers your hardware. It may be a good fit, but don't assume it reproduces every MDT task sequence step exactly.

One networking wrinkle: no deployment tool can make PXE independent of DHCP and network configuration. Clients need to receive the relevant boot responses. Whether you need a relay or IP helpers depends on the network layout, particularly when clients and deployment services are on different subnets.

If MDT PXE already works, that's a useful starting point. But I'd separate the question of reusing that setup from the question of whether a replacement needs any network changes.

FOG is another option if you're willing to put some work into the setup. I wouldn't assume it'll be a drop-in MDT replacement, though. Test the task sequencing, model-specific drivers, naming, and Secure Boot requirements before choosing it.

Acronis Snap Deploy is worth comparing too. It supports PXE and has Universal Deploy for handling drivers on different hardware. Deploying across subnets can still require network helpers, so check that against your topology.

For Windows and Office activation, verify the licensing and activation method you already use rather than treating it as purely an imaging feature.