I both love and respect the time you're putting in to try and make it perfect - but don't panic and overthink it.

If you include having a cup of tea at work, most of us are fine with "whatever hot water is available, from whatever limescale-ridden kettle is available, on top of whatever bog-standard teabags are in the shared kitchen, milk if it's not past the expiry date, without milk if it is".

You can get perfect temperature water, pre-warmed cups, filtered water etc, but most of the flavour in a cup of tea comes from a) leaving the tea bag in long enough to make sure it's strong enough, b) how hard the tea-drinker's workday or journey was.