Are there any benefits to using a dedicated tag provider for each project? Is using different tag providers in the Gateway only for organizational purposes? Are there any drawbacks if I place 300K+ tags in the same tag provider in the folder structure?
It is mainly organizational, to make it possible for projects to have different default hierarchies. (Each project has a default tag provider property.) Do note that UDTs are not sharable across providers. You would have to place the definitions in all providers that need them.
Have you read the docs over at:
Tag Providers - Ignition User Manual 8.1 - Ignition Documentation (inductiveautomation.com)
How it may benefit you really depends on your system architecture. Try to optimize your system as much as possible.
Got it. Thank you so much!