@frank_hezemans glad you found it useful - I just release v0.2.0-alpha, summarized here: Chkptstanr v0.2.0-alpha: checkpoint brms and cmdstanr sampling
However, as I note there, I recommend using it with big caution. The package has a big issue with how it deals with the adaptation and warmup, as you can see in the discussion here: What is the point of doing extra "typical" initial warmups not done when not using chkptstanr? · Issue #10 · venpopov/chkptstanr · GitHub
If you use it I recommend setting iter_adaptation (previously iter typical to a much higher value). In essence, you cannot do checkpoint ING during warmup, as the real warmup is the initial adaptation, and not what the original package calls iter_warmup