Data centers reuse water by recirculating the same water through their cooling systems multiple times. According to Google, this practice saves up to 50% of water when compared with “once-through” cooling systems.

However, eventually this reused water needs to be replaced with new water, due to the risk of scale formation or once the conductivity of the water is too high.

The need for new water results from the build-up of scale-forming minerals in the reused water – such as calcium, magnesium, and silica, which become concentrated over multiple evaporative cooling cycles.

Ultimately, the spent data center cooling water can be treated and reused (or recycled) for other purposes such as irrigation or toilet flushing.

https://dgtlinfra.com/data-center-water-usage/#:~:text=What Happens to Water Used,a local wastewater treatment plant.

Love my mikrotik hex they have more advanced hardware and I just use a tp link as an access point. I migrated from a ddwrt and it’s got all the features you could ask for

Vaultwarden is a go rust fork that is significantly lighter for 1-2 users super easy to self host

Edit: rust fork

Have you looked into vaultwarden? That supports TOTPs