Anecdotal contribution…
I live in Phoenix and have had in my garage for about 5 years now, a 65g reservoir for RODI water supplied by a 4 stage, 75gpd unit with a TDS meter.
I have never had any issues with the quality of the RODI output, lifespan of the filters or resins or unexpected contaminants. (I do keep the extra resin inside however).
The garage is routinely > 110 deg in the hottest months. At night, it does not drop below 90 deg. This weekend, ambient temperature was 118 deg outside of the garage. And when someone pulls a car into the garage….well it’s pretty friggin hot in there.
I would consider these “extreme” conditions and no issues that I am aware of.