also i would not put stations on the main track and if you want more compact intersections make them forward and turn right only, then alternate the directions of each track every other line. eg left/right/left/right for horizontal tracks, and up/down/up/down for vertical ones
They're not
technically on the main track, there was never a plan to have 4 track chunks, if a train is stopped other trains can use the true "Main" rail to get around them. Also I've done no testing

I'm making a lot of throughput sacrifice to try to keep stuff as versatile as I can, that's why I'm also using a 1-2-1

This is what stuff looks like all attached, in theory there should always be some kind of path around blocked up sections it's kind of brute forced with the number of paths trains have. Each cell has 4 train stations so 4 inputs or outputs which handles most crafts, if I need more I can break apart sections for more stations or just have belts cross into another cell and build an unloading area.
So far stuff seems to work well enough and I'm pretty sure this is the perfect foundation to perfect preventing clogs via logic.