Last campaign I ran the paladin was so proud of herself for smiting down a couple lesser demons and gushed about it for the rest of the week. So for the next 3 arcs of that campaign I snuck in a cambion who was hounding the party and got his lights clocked in multiple times just knowing the dopamine release it gave that player even when every 'challenging' encounter crafter for that group was done in about 5 terms and took me nearly and hour to craft ahead of time.
To me as the DM it's your job to learn what quirks or functionality of the players particularly enjoy about their characters and find a way to sneak in encounters, puzzles or situations that give that player time to shine and enjoy it. Even and especially if it trivializes the challenge you put into it.
The number of online dms I hear complaining about flight speed races and flight spell boggles my mind. You just got licence to make 3d puzzles and encounters. And also show those players why spiders in magic the gathering had the ability to defend against flying creatures through out the 90s