Just do what you feel comfortable with.
I understand the discomfort about guns and weapons as toys, it feels uncomfortable even more do with do many wars going on and horrendous killings in the news every day (Ukraine and Russia, Israel and the Palestines, Syria, Iraq to name a few)
How can shooting and killing be a kids' game with real wars going on.
Despite that, my boys have nerf guns, water pistols and even an air rifle.
Is that some kind of cognitive dissonance?
Trying to think about it a bit more deeply, I think fighting and war are part of what we humans are about. Sadly. And play fighting is therefore also part if our dna.
Playing is an important part of growing up, it is not just "fun", it prepares children for adult life.
It appears all children, with some exceptions, have a love of "winning", of running faster, of shooting/hitting/aiming/fighting, as well as the need to get on in a team.
We recognise the team player thing as a key to human survival. We are more uncomfortable with our children's love of shooting/fighting. Most boys seem to like wrestling or martial arts too.
I am not sure you or I can fight these hard wired needs. I respect people who do though!
So what will you do OP? I "gave in" when they turned 5/6.