Hi, I'm on a somehow "comparable" (but very different scenario) project in terms of using same DS18B20 and arduino 3.3V, a mkr SAMD21 in my case, and trying to get the longer autonomy I can.

The best option I've seen so far seems to be to use the (best option) TPS61291 or (alternate option) TPS61221, as the first seems to be designed for this use cases, and the second has enable option to switch it off. All those seemed to me (newbie here) better than the TPS you indicate.

For my use case, the "low tech" option indicated by @mfalkvidd could fit very nicely, so I'll dig into that option.