I am an experienced slot player and my advice to anyone who asks such a question is,yes absolutely you should stop.I don't know what is going on behind the scenes but surely all casinos and all slots have started paying less and the RTP is greatly manipulated in my opinion.The only games I suggest are skill ones like Poker as my top choice where you compete against other players and sport betting,everything else is not worth anymore.
There’s no such thing as manipulated RTP since slot games software is being audited for their license before it can be distributed to the casino for use. RTP is programmed based on the declared RTP. A house edge of 4% which is an average on all slot since a slot RTP average range to 96% will surely give you a little bit disadvantage in long term but this can’t be feel immediately if you are just playing for few spins.
Slot games is very entertaining and you shouldn’t gamble casino games if you are aiming for +EV games since it doesn’t exist on any luck based game. Also not all people can win in poker so you might loss disastrously if you will match against other players with better skills.