I went through a good majority of alternatives (types and manufacturers) over a few of the lockdowns and honestly, without massively compromising taste, texture and look, you're going to really struggle with tea. Oat, almond, soya or cashew is probably the better alternatives although they generally give it a little 'off' taste (and sometimes sweet) but it will look like you've dredged a canal.
Coffee you can get away with most alternatives although Minor Figures Barista oat alternative is one of the best (little expensive), especially if putting it through steam as it doesn't appear to split like other oat alternatives (or other alternatives full stop).
And the worst alternative is easily hemp, one sniff and the smallest of swigs was all it took for it to end up down the sink; absolutely horrendous.