I used to use oat milk in tea, having previously tried various kinds of soya and hemp milk. Soya is environmentally bad and hemp milk is expensive. There was just one oat milk that was labelled 'made in the uk' so I stuck with that, until I discovered tea with lemonade.
Not your standard floor sweepings tea bags but proper whole leaf tea. Ceylon long leaf black tea can be bought on ebay and Gunpowder Green Tea from a Rusholme Indian deli. These are continental style teas, less bitter than the teas marketed to be drunk with milk in the UK.
I've treated myself to a glass teapot with a diffuser which can be closed off to prevent stewing and makes clear up simple. Tea with lemonade is amazing. About one quarter to one third lemonade depending on taste. It still works when the tea is cold, in hot weather it is better.
The only tea bags I use now are for Rooibus tea if I want one at night, with lemonade of course.