Homelander's superior strength, flight, and heat vision give him the edge over Spider-Man's agility and spider-sense.
Homelander is physically stronger and more durable than Spider-Man, with the added advantages of flight and heat vision. Spider-Man's spider-sense would alert him to Homelander's attacks, and his agility is exceptional, but Homelander's laser vision is difficult to dodge indefinitely and can cut through most materials instantly.
Spider-Man's strength lets him lift roughly 10 tons; Homelander's strength feats suggest he operates in the hundreds-of-tons range at minimum. This gap means Peter's punches would annoy Homelander rather than hurt him, while Homelander's hits would be devastating.
Spider-Man's advantages are his intelligence, web-shooters, and superior agility. Peter could potentially blind Homelander with webbing and use hit-and-run tactics. But Homelander's heat vision gives him a ranged attack that webs cannot block, and his flight means Spider-Man cannot escape by swinging away. Homelander's durability also means Peter's standard attacks would have minimal effect.
Homelander is significantly stronger, can fly, and has heat vision that cuts through almost anything. His durability means Spider-Man's punches would have minimal effect, and his flight negates Spider-Man's mobility advantage.
Spider-Man's spider-sense provides precognitive awareness of all attacks, and his agility lets him dodge what he senses. His intelligence and web-shooters give him creative tactical options, and he has defeated stronger opponents through cleverness.
Homelander wins through superior raw stats and heat vision. Spider-Man would put up a fight through agility and intelligence, but the strength and durability gap is too large for Peter to overcome.
Homelander also fights
Spider-Man also fights