Welcome to the forum!
To try to prevent some frustration later, let me clear this up. You do not submit Pokestops, even though that is what the in game prompt says. The Web Submit form has it stated correctly that you are submitting a Wayspot. Whether an approved Wayspot will be used as a Pokestop or gym depends on the S2 cells, according to community observation. Niantic does not acknowledge this, but this article explains: https://pokemongohub.net/post/article/comprehensive-guide-s2-cells-pokemon-go/
As for how long it will take, that varies. At approximately 20-24 hours after you make the submission, a machine learning model filter will check it. If it does not recognize anything that it has been taught could be eligible, the “automated process” can reject it. If it isn’t rejected, it can either go into in house voting, community voting, or remain in queue for a bit. If it goes into in house voting, they can either decided it, or put it back into queue for community voting. Once it goes into community voting, it can be anywhere from a few minutes to a few months. If it gets that old without a decision, Niantic seems to pull them for in house review.
tldr: I usually get a decision within a week or two these days, but can’t predict how long yours will take. It can depend on how many active reviewers your area has, and how easy or difficult yours is to decide.