Fighting naps?

Does anyone else have a 5 month old that fights naps? And I mean physically fights. My 5 month old kicks, screams, flails his arms when it’s nap time. I usually have to pin his arms to the side and hold his legs to me to calm him down, all while he fights to get free. It’s so upsetting. He usually calm down and is asleep within 10 minutes, but those 10 minutes are ALWAYS a fight and I worry it’s traumatizing to him. It certainly is for me. I dread nap time.

I watch his wake windows, I put him for a nap at the first sign of tiredness, and I follow a nap routine. I change him, put him in a sleep sack, and read a story. He’s fine through all of this and then the fighting begins. It’s almost like it’s part of the routine too. His room is dark (I covered the windows) and there is a white noise machine. The weird thing he doesn’t do this at night. He falls asleep pretty easily at night and wakes only once or twice to eat.

I’m sure part of the problem is he’s overtired because he will only sleep 30 min max at a time. But like I said I nap him at the first signs of tiredness (usually 1.5 to 2 hours after last nap).

What am I doing wrong? Is this just normal?