To answer the question in the OP, I have 78 items in my "Applications" folder, though obviously a fair number of those are default OS apps. Quick count suggests I usually have at least 30 of those running pretty much all the time, running from small toolbar programs like Popclip and Amphetamine to bigger productivity stuff like Excel and Scrivener. Outlook, Messages, WhatsApp, Teams, Safari and Fantastic are always open in windows scattered around my desktop.
On a base 2018 i3 Mac mini with 8gb RAM and never really experience any slowdown or issues at all other than when accessing a NAS drive in Finder which sometimes slows down.