I can strongly recommend the mobile app Flora Incognita for quickly identifying plants. It’s made by one of the German universities so it’s free, don’t have ads, and don’t collect your personal data. I even showed it to my mum and she loves it
I use iNaturalist for plants and animals, mostly insects (and Merlin for birdsong recognition).
No ads, non-profit, contribute to research, etc. It also allows you to find out what others have spotted in your area. I like the range maps, the images across seasons, and other seasonal information.
The actual ML-based recognition is somewhat hidden, I think that part of the UI needs some work; it seems like it was made for researchers first then hacked for non-experts to use.
It is a pity that, while their focus is on openness and accessiblity, neither Flora Incognita, nor iNaturalist or PlantNet can be installed from the F-Droid appstore. I unfortunately don't use Google Play, so can't testdrive them.
How does it compare to iNaturalist or observation.org which are like the 'standard' ones?
+1 for Flora Incognita. This is what apps should be.
Besides the utility for users, Flora Incognita is also a massive crowdsourcing project for science: They use the GPS location of photos in combination with the identified plants to build a temporo-spatial database of confirmed plant sightings. (To my knowledge no link to any personal data of users.)