When I upload a new video I usually try to put us many relevant tags as possible, but a thought crossed my mind - Can you put too many tags in your video causing search engine to treat your videos like a spam or something?
Yeah, this hits the nail on the head and the bit in bold is the only thing that could get a channel in trouble if they don't follow that guideline. If a channel puts tags not related to the content of the video in an attempt to piggy back off someone else's brand or success, then it's considered "misleading metadata" by YT and can result in a community strike.I do think your tags should be focused on what's most likely to bring people to your video and at the same time they should be representative of the video.
See @babyteeth4 's and my post above - Those tags are fine so long as they do indeed reflect the content of that particular video.For example in my last videos I've used -
Mario,Super Mario,Super Mario Odyssey,Super Mario: Odyssey,Odyssey,The Odyssey,gameplay,cappy,top hat mario,frog mario,transformation,ghost cap,ghosts,mario odyssey,weebster,Let's play,review,playtrough,commentary,ending,secret moons,secrets,moons,purple coins,coins,outfits,switch,nintendo,nintendo switch,full,guide,boss,all bosses,New donk city,city,donkey kong,luigi,princess peach,super,theme,odyssey theme,mario music,complete,secret moon,part 5,rabbids
Same hereafter making over 1,000 videos across two channels, I've decided that it doesn't matter. Some videos succeed, some don't