Skeletons and battletech mechs, if you are fixed on 40k then necrons - metal skeletons.

>>98743966
Any. Just pick up a fucking brush.

My two go-tos I'd recommend for a new painter are either loyalist space marines or black orcs from fantasy

To paint on easy mode: Pick a color scheme where your primer color is the base coat for a large part of the model. This can work with marines, necrons, tyranids and tau, to name a few. In fantasy it works with lizardmen, and parts of the orks range.
Pick a subfaction you get transfers/decals for. Decals aren't hard. And a model that basecoated, has one accent color, and some decals, will look passable on a table.
For basing, choose a theme that lets you use a texture paste and call it done.
This won't be a pretty army, but it will be leagues ahead of grey tide.
To paint on fun mode, choose models you want to stare at, because you'll be doing that for a while. And just start practicing on models you like.

All wrong answers so far, the correct answer is the mini that you like and are invested in

>>98747423
no this is wrong because your first mini is gonna look like absolute dogshit and youll be pissed you ruined something you liked. start with something youre not invested in