Bob, I sympathize. I think this is a Windows 10 thing. After the latest upgrade I cannot change several default applications. Believe me it's not through lack of trying. I've tried every method available.
Can you change it from here, or is this where it doesn't show:

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BIAB & RB2026 Win.(Audiophile), Windows 10 Pro & Windows 11, Cakewalk Bandlab, Izotope Prod.Bundle, Roland RD-1000, Synthogy Ivory, Session Keys Grand S & Electric R, Kontakt, Focusrite 18i20, KetronSD2, NS40M, Pioneer Active Monitors.