Plantuml for drawing pictures together with the C4 Plantuml Plugin is helpful. i.e. you make high level overviews of your architecture and then „zoom in“
For decisions a table with some explainatory comments why you have decided to use this one thing and which alternatives you have considered and why those did not make it, helps. You can look up ADRs. (Decision Records)
Comments
Plantuml for drawing pictures together with the C4 Plantuml Plugin is helpful. i.e. you make high level overviews of your architecture and then „zoom in“
For decisions a table with some explainatory comments why you have decided to use this one thing and which alternatives you have considered and why those did not make it, helps. You can look up ADRs. (Decision Records)