Was it ever any faster?
That iMac had only a 10/100BASE-T ethernet port; it was not until May 2005 when iMacs had the modern 10/100/1000BASE-T port protocol. Those ethernet speeds are similar to wired connection speeds of our G4 eMAc that has the same port specs.
The wireless hardware is also slow on that model: Optional AirPort Extreme card (802.11b/g).
By comparison your Mac Studio is a race car. ITs comm specs:
Communications
Wi-Fi
- 802.11ax Wi-Fi 6 wireless networking
- IEEE 802.11a/b/g/n/ac compatible
Bluetooth
- Bluetooth 5.0 wireless technology
Ethernet
- 10Gb Ethernet (Nbase-T Ethernet with support for 1Gb, 2.5Gb, 5Gb, and 10Gb Ethernet using RJ-45 connector)