I have done REtipster and LandAcademy, been investing in land for 3 years now. I really liked Seth's course, it was my favorite of the two that I've taken, I can't speak to the rest. I really like the business focus and data-centric focus that the LandAcademy community leans towards. They're both good and you'll have success with either. See what who's style speaks to you. Listen to both of their podcasts for a while and you'll lean one way or another. LandAcademy may be "capped" at 500, so you may need to go with Seth's but you won't be disappointed by the educational material, it's all there, no doubt about it, you'll be up and running in no time.
As for my experience land investing. In my experience it is definitely a job more than passive income (yes you can create owner finance notes for "cash flow" but you need to constantly be buying more as those dry up in 3-5 years typically), you need to constantly be sending direct mail campaigns, talking to buyers and sellers, posting property ads, etc. I have ~10 properties in inventory at any time and buy sell 2-3 per month. There's a lot of paperwork and you'll want a good CRM. That being said I like the business and am using it to generate capital for other long term buy and hold "passive" income models.
Best of luck out there!