Welcome!
I use a $2750 USD NAD M10 "streaming amplifier" from their Masters Series (the value leader of the series). It's a very flexible, compact, and thoroughly modern all-in-one component. It handles analog, coax, optical, Bluetooth, HDMI, USB, Tidal, and Radio Paradise inputs and outputs to headphones (Bluetooth), preamp, subwoofers (2), and speakers. Can be controlled via it's big/clear touchscreen, Windows, Mac, Android, or iOS. Uses NAD's in house BlueSound operating system, so no additional software needed. Makes digital easy.
Conservatively the M10 provides 100 watts per channel. Realize that the relationship between watts and dB of gain (loudness) is logarithmic meaning that it takes ten times the watts to produce twice the loudness, so to make the Harbeths sound twice as loud would take 1,000 watts (which is way more than they're rated for). So 100 watts per channel would be fine.
Just a suggestion, but in my opinion a hard one to beat.