Brakes like the Tektros come in a left and right.
Some brake lever models, you would not notice the difference between a left and a right, but some you would notice.
I mention that in case you have a bike coop or bike charity in your community, they often have bins of used parts like brake levers. When I built up my rando bike over six years ago I used an older style right hand Tektro lever on the left side (right side in photo) because that is what was available at a bike coop. That older style can be used as a right or left without noticing the difference in lever shape.
But, some of the newer levers, such as newer Tektros, you would notice the difference between right and left.
This photo of a newer Tektro is from Velo Orange website. I think it clear the right and left would feel quite different so you would have to make sure you get the correct one if you buy one of this model out of a bin.
In my case, there were lots or right hand brake levers in the bin, I think a lot of people that bought pairs to build up a 1X bike donated the unused right hand levers to the bike charity I bought mine from.