Starting with Audacity 3.2+, the built-in GVerb was removed because it crashed on some systems. You can now install it manually as a VST3 or use the LADSPA version (Windows legacy).
As Audacity evolved (especially versions 2.x through the current 3.x), many legacy plugins stopped working or were retired by their developers. GVerb was largely a 32-bit plugin. As operating systems shifted predominantly to 64-bit architecture, and Audacity updated to handle modern standards, the old GVerb files became incompatible or unstable. gverb audacity plugin download
Since GVerb is defunct, modern users should look for contemporary free alternatives that function identically. We recommend: Starting with Audacity 3