Has it been 24 months since you received the SW bonus? If so, I would cancel now but hold off on applying until a better SUB comes along, hopefully soon.
I would keep your Chase Slate, no point in closing a card that doesn’t have an AF that you’ve have for 5 years. And yes, keep the BOA card open.
Another good all-around card is the Freedom cards. it doesn’t appear you are interested in Biz cards?
Other than a VERY occasional sale on Poshmark, I don't have an activity to support a business card. And yes, my SW bonuses were well over 24 months ago. Those cards were issued in 2011 and 2015.