I spent some time to build my own web-based markdown editor, and was using minisearch[0] to index and do fuzzy search on my notes. I've recently switched to Obsidian and plan to make a similar extension in the next weeks.
If you're on a Linux system and the notes are just text files a
grep -rn . -e 'search term'
is probably sufficient. Use
-rnw
If you're looking for whole words.
I'm using Roam and I still have this issue.