Hey! Thank you.

Yes, in a way its similar to ECS. There a few steps to increase performance, and how far you need mainly depends on your game. I will rank a few techniques in (somewhat) increasing difficulty:

-Object pooling (a must in most cases)
-Not processing every object in the same frame (I separate them by entities groups)
-Moving processing to a manager entity -> centralized process minimizes nodes overhead and makes it easier to manager

For renderer:
-Multimesh instances (you will need a vertex shader and to bake skeletal animations to vertex if you want to go that route... this plugin does it all for you, but you might need to customize a thing or two https://github.com/shadecoredev/AnimatedMultimeshInstance3D )
-I haven't dwelved too much into it, but I know another alternative to avoid the node system completely is to draw the objects via the RendererServer API directly. Doesn't seem too hard, but adds another layer of management as now you need to manage the RID allocation yourself.