Long Range WI-FI on 5G modem is no where near what my DSL modem had.

The DSL modem likely had a much larger and stronger antenna than the cellular smart hub does. The cellular hub also supports fewer devices than the DSL modems. The number of antennae can also be a factor as would the frequency being used.

Wifi was never really designed to cover 2.5acres on standard residential gear so it's surprising the DSL modem you had mostly could cover that distance from indoors. Standard wifi has a range of maybe 20m / 66ft for average indoor access points, or less depending on environmental factors. Which DSL modem did you have? For me I have the T3200M and there's no way the wifi from that would cover 2.5 acres. I wouldn't get signal at even 100ft also unless I was direct line of sight to the modem. My non-Telus router with external antennae is no better.