I started this project in some capacity (initially with Godot) back in 2021-ish. I started and stopped a lot with Godot and my own engine. I had a mostly working base engine in several iterations over the last year or two. I stopped working on my original engine earlier this year due to finishing up and defending my doctoral thesis. Thankfully, over the course of the last few weeks, I have refactored and recreated the base components of that game engine. The engine includes the following things so far:

1. Rendering - sprites, grid maps (which will form the basis for the terrain), and an entity picker

2. UI base - this relies on Dear ImGui for now. 

3. Dynamic camera (not shown here) - you can move around the world using the WASD keys

4. Base input systems - keyboard, mouse

5. Scene Management (not shown here) - the ability to switch between scenes

6. Entity Component System - all objects including the tiles shown rely on an ECS system extended from EnTT

EDIT: Also added - terrain generation. Obviously, it needs some tweaking, but the general basis is there.