wood are better. aluminium will sag not because some1 in the actic but because the weight of the roof.

if you engage termite proofing, part of the job is to spray the roof wood support. else you can buy termitox from ACE, dilute with water and spray it yourself. it will solve the termite issue for 5-8 years easily.

sag frame will need to be total replace due to safety which is more costly.

also ask your contractor to add wood beam to make the roof inaccessible from outside as most of house break in is via roof.