Sorry to hear you are finding it to be slower, we wouldn’t expect that. The global subspace expansion isn’t enabled by default so shouldn’t affect the code you are running.
Can you please format your code (Please Read: Make It Easier to Help You) so it is easier to read?
Also, could you try running:
# Compile the code first
ITensorTDVP.tdvp(H,-0.1im,psi0;nsweeps,maxdim,cutoff,outputlevel=0)
# Now run and time
@time psi = ITensorTDVP.tdvp(H,-0.1im,psi0;nsweeps,maxdim,cutoff,outputlevel=1)
i.e. run that line twice instead of once? Julia compiles the code the first time it is run, you may be measuring both the runtime and compile time and perhaps the compile time, not the running time, got slower.