I almost used one a year ago when my son was headed to the US for school and needed something notarized, but wasn't confident it would be accepted and ended up at the consulate.
Just this past week I needed a replacement AMEX card, and they said they needed a notarized copy of my passport. Thankfully, they gave me a link to an online notary called NotaryCam (they are contracted with AMEX so it was free for me).
I uploaded a scan of the passport, then used my computer camera to take a picture. The AI approved it on the second go, and then I was able to schedule an appointment for a day later (times appear to be 24hr availability).
I went online and met a woman in Virgina (4am there) and we were done in 10 minutes. She sent it to AMEX and the card is on its way!
The service says good in 50 states. I think COVID pushed state legislatures to permit the service.
https://www.notarycam.com/
Website says $79 if you are located overseas. More than the consulate, but huge savings in time. I imagine there may/will be competing services that are cheaper.