If 818v3 is out of budget, definitely consider 861v4.

If you go for an 861v4, the best performance vs value is one with the linear power supply upgrade and ID40 card for Roon streaming. You’ll also need to source an OA13 balanced output card (assuming you go balanced into your 577). Unbalanced output card is the OA03. Both are 24 bit/192 kHz capable DACs, which sound very nice indeed.

HC: 861v4/ID40/LPS, DSP5000, DSP5000VC, DSP3100, SW1600, HD621, Oppo BDP-105, Sony VPL-HW55ES
2-Channel: Oppo BDP-105, TEAC VRDS-7/Trichord Clock 3/PSU, 551, Quad 303, Harbeth Compact 7ES-3, Kimber cables, Russ Andrews mains and supports.
Previous Meridian: 5000C, 5200SL, 7200.2, 6000, 562V.2, 568.2mm, 800v4, 808.2i, 818v2/v3, 861v8, 502