Is there any R package for time-varying mediation but with invariant exposure and outcome

Question

[Phylicia]

Hi ~ Is there any R package or other programming tutorial for time-varying mediation analysis? And at the same time, the exposure and outcome are invariant.

I found one, but the outcome is also time-varying and repeatedly measured. Is there any tutorial for invariant outcome? https://cran.r-project.org/web/packages/tvmediation/vignettes/Time_Varying_Mediation_Analysis.html

Thanks a lot for your kind help！