In the comics, Spider-Man stumbled onto the Venom symbiote during the Secret Wars event while he was on the Battleworld with other Marvel heroes and villains.
Sure the Venom movie could come up with an alternative reason for why a symbiote-powered host has arachnid-themed powers, but it just won’t work as well.
More importantly, its time with Peter also resulted in it acquiring all of Spider-Man’s super powers.
So even though a symbiote-powered host can be physically enhanced and shape-shift, Venom can’t rock abilities like wall-crawling and the Spider-sense without having been latched on to Spider-Man for a long time.