I did the following certs a couple of years back, all via the above scheme so free exams:
Azure Fundamentals
Azure Data Fundamentals
Azure Power Platform Fundamentals
Azure AI Fundamentals
Didn't do much study for them - basically prerecorded online training sessions (about 5hrs total for each cert) and then about 90mins of study for each of the first two, the second two I had very little prior experience of so did maybe 3hrs of study for each.
For these particular ones I didn't bother doing any lab work, as I knew they'd be theory based.
One word of warning, the online training days do NOT cover all the course content (they don't make this clear, so the first exam I just went into and got kind of surprised by a couple of questions), so I'd recommend skim reading the MS Learn pages afterwards to pickup the extra stuff (as per above I just skipped any sections relating to use of labs).
So in summary the foundation certs you can do with about a day of study each.