I use bar end friction shifters with 10 speed Modern group sets, and it works great, in fact I did index them , but it felt better in friction mode, so I’ve been happily doing that for some time, I still have a bike with flight deck gear & break levers, & I’m thinking about changing that one over to friction shifting as I’m so happy with it, you also end up with a gearing system which is easy to move with no faffing about trying to index, you just connect up the cables & away you go, simple & very satisfying & cheaper.