Hah, well I said there are many platforms, not necessarily that I knew much about them – any web search will spill a lot, everything from Moodle to Kahoot to Peardeck.
So you want something with a good variety of exercises like H5P, or maybe more specifically, what kinds are you looking for? Are you seeking open source? hosted? self hosted? I have not even used many of these much less installed/operated them. But if you can state more about what kind of assessing you want to do and what kind of reporting it should do, then… well someone else here might help.
See? Ask me anything, and I reply with more questions.