Definitely not just you.

Often, though I know exactly the info required to find a message, Thunderbird comes up with no results. I've found that "repairing" the containing mailbox renders the message findable.

Not sure when things got this bad, but I can well recall in the past Thunderbird's search being fast, thorough, and reliable.

its takes a few seconds parsing all the accounts/folders (as I have an indecent amount of email) but it never had any trouble finding things

Search never works for me. I use quick filter. It's slow, but works.

Yeah, the "normal" search is for the desperate.

Quick search is where it's at. Keeps the view sane and you select which fields to search (subject, recipients, body), the downside is that you have to know which folder to look in, which can also be an upside to narrow it down (I know that's also possible in the search UI but this is easier)

Some years ago it used to work great, but then it changed to searching for words only. Or so it appears.

Use recoll