Theoretically it should work, but the sodium carbonate produced by the reaction tastes slightly astringent and affects the taste, and secondly, the temperature of the sodium bicarbonate to decompose completely will be above 100 degrees Celsius, and the sodium bicarbonate that is added may not decompose completely, and the amount of carbon dioxide and so forth is also a problem.

However, I have not made lemonade, but I think fruit acids should work. You can go buy some fruit with a high fruit acid content and juice it to add to the soda and it should work, but I haven't tried that either.

Through the Baidu encyclopedia, lemon juice should be able to replace, roughly estimate the general 100ml of lemon juice can react 6.1875g of sodium bicarbonate. It's not like you're going to be adding that much sodium bicarbonate. So it should be feasible

In fact, in Taobao or something on the site above the citric acid is sold ~

Not seeking to adopt, only to help you.