The hard part is usually knowing what +not+ to write down. Every system I've seen eventually drowns in low-signal entries.
The problem always is that when there are too many memories, the context gets overloaded and the AI starts ignoring the system prompt.
Definitely not a solved problem, and there need to be benchmarks to evaluate these solutions. Benchmarks themselves can be easily gamed and not universally applicable.
I guess the markdown approach really has a advantage over others.
PS : Something I built on markdown : https://voiden.md/