70% RH after harvesting in the First days ok?

Well, the plant is dead, so it's not transpiring. It may be alive the first 24h but chopping it down will definitely close the stomata. Yes the amount the plant material releases each day will be reduced over time. You don't need to use a tent. A dark room is good enough. Leave the tent-door open at the least. A fan moving air but not directly pointed at the buds or creating big breeze across them -- "some" circulation is enough. If you are keeping it zipped up, this would probably fix your RH problem, unless it is also ambient RH%. Otherwise dehum is all you can do... adjust setting until target RH is consistently reached. Easy peasy. cheap hyrometers are often +/- 5% or more. It's possible your dehum is reading low and your hygrometer is reading high relative to error%. Possible one is total junk, too. So, you'll want to clear that up one way or another so you can trust the readings. A third hyrometer or a known RH% etc. You want it 65% or below.. preferable 60%, give or take a couple just as you want for curing. 65% and above increases risk of microbial growth.

Set your dehumidifier less than 60 mabe 55% and that will make the room close to where you want it. you are going to have slightly different readings but I found to get the 60 percent I have to set it lower like 55-58. you really don't want it that high although it's normal for it to spike a little the first day. less humidity 50-60% in the first few days is safer and going to cause less problems than going higher than 65%