Technology is more associated with sci-fi, which is understandable as it often has exciting fictional toys such as teleporters, faster than light travel, and cyborgs.
However, it’s also a matter for fantasy. Given that many stories take place in an essentially medieval English setting there are crossbows and longbows and mangonels. Gunpowder is either not used at all or just being discovered.
There is some scope for going down a different path, without having more advanced technology.
In the conquests of Alexander, the battle weapons used were relatively simple. Spears, swords and shields were the order of the day. The difference came with siege warfare. Alexander, benefiting from a corps of damned clever Hellenistic engineers, was able to utilise their expertise and the manpower he had available to devastating effect in sieges.
Alexander the Great had absolutely massive battering rams, and regularly built siege towers that were staggering in size. Aided by his position as king, commander-in-chief and the lack of human rights laws, he used his own army and any nearby peasants to commit huge acts of manual labour. In his epic taking of Tyre (a walled island city) he had a mole more than a half a mile long built out to sea, enabling his artillery to get into range of the walls.
The Byzantines used, for a time, a brilliant concoction known as Greek fire. This was an oil-based substance which saved the city on numerous occasions by (almost literally) setting fire to the sea. Other nations were ignorant of its ingredients and terrified of the flames, which floated on the water (as it was oil-based) and often devastated enemy fleets.
Although not based on technology, Hannibal came up with some interesting tactics. After the Second Punic War, he worked for Rome’s enemies, and in a naval battle came up with an innovative idea. He had snakes collected and put into clay pots. These were then hurled onto enemy ships. The clay shattered, the snakes escaped, and the Romans were distracted and terrified by the sudden appearance of slithering reptiles on the deck.
The Romans themselves used (as seen in the opening battle of Gladiator) clay pots as siege ammunition. They were effectively huge petrol bombs, with the outside lit and the inside filled with combustible material. When the pots were fired, they landed, broke apart and burst into flame.
Technology does not necessarily improve over time. It usually does, but not always. Consider Concorde. Faster than any commercial passenger plane today, yet in a museum.