Update for best SS amps for Harbeth 40,.2 anniversary spks

Seems these speakers have fallen off "the grid" of late. Latest input on amp recommendations is several years old.  Many changes to the industry, including speaker choices but I like mine a lot...my third pair of Harbeths...SLH5, 30.1 and now 40.2 anniversaries for the last 2 years.

New house, new large room (somewhat "live"} hardwood floors with wool rug. Best sound so far with my big Harbeths. Kinda surprised there's no bass boom at all. (about 5 feet out from front wall where I like them best) Thinking of a pair of Rel subs but, either way, feel I should consider amp upgrade (no tubes) from a Pass Labs X250.5 (15 watts per at class A before A/B)  Benchmarks ruled out.

Rossi's are probably too pricey. Like the idea of monoblocs. Specially like Class A.  For A/B's Considering used Hegel (non integrated), Luxman, sim audio, Ayre and am VERY curious about AGD Audion mark 3's class D, but at 150 watts per channel wonder if that's enough for a big room even though I sit near field about 9 feet, ear to tweeters. Bigger AGD class D amps are out of my budget and not likely to come up used. So much praise for the lil monoblocs.

Anyone using the Audions with the big Harbeths??  Thoughts? Impressions?

System: Project rs2t cd transport, Laiv Harmony dac, Benchmark LA4 preamp, Pass Labs X250.5, Puritan power conditioner for all cept for the amp.

Thanks for any input