I have seen this before, and it appeared to be fixed in an older version of Audacity (3.4 IIRC), but it is back again. Whenever I hit play, with multiples of the same plugin in the realtime FX slots, Audacity immediately crashes and gives an “exception code 0x1”. I am not technical enough to know what to look for in the crash report, but I have sent TONS of these reports to Audacity, to the point that you’d think it would be noticed & fixed by now.
Anyway, putting any given plugin in a realtime FX slot and master FX slot is fine, so it’s something specific to multiples in the realtime slots. FWIW, I often do this with EQ’s, for a pre-compressor eq and one at the end of the realtime chain (usually FabFilter Pro-Q4). Same goes for a compressor (Elysia Alpha Compressor) where I need to use its soft clipper section separately from its compressor section (the two interact if you use them in one instance).
If there’s anything else I could test, I’m all ears.