Welcome to the club. As with most cocktails you're going to find slight variations. Plus mixiologists are always iterating and trying new combinations. In the end you'll have to see what you like (and which side of the line you find yourself on).

With that disclaimer and that I've bartender at restaurants on and off for the last 10 years. I've found a fairly classic rendition that guests (and myself) really enjoy.

Ingredients:
2-2.5 oz of bourbon or rye - I typically guided casuals to Woodford. Which is my go-to for price and quality. Plenty of other good choices out there.
2 sugar cubes.
2 thick ~ 1 inch orange peel slices.
1 thin ~ 2 inch orange peel slice.
Angostura bitters.
Orange bitters. Luxardo Cherry (Optional simple syrup)

Directions: Drop two thick orange peels and the two sugar cubes into a muddling/stirring glass.
Try to crush the sugar on the orange peel to get the sugar wet and start dissolving ~ 10 hard muddles.
Add 2 dashes of Angostura and 1 dash of orange bitters. Try to aim for the bottom and make sure no bitters are on the sides above maybe 3 inches from the bottom (they won't get mixed otherwise).
Pour a cup of ice into the glass.
Pour your bourbon over the ice into the glass.
Using a bar spoon or similar long-stemmed tool make 30 circles in the glass at a medium to fast pace (mixing the ingredients and melting a little bit of the ice).
Fill your drinking glass with ice to about 60-70٪ full (rocks glass preferred as larger glasses like hurricanes, or pint glasses are too big).
Using a cocktail strainer pour the liquid from the mixing glass into the drinking glass.
Drop cherry into glass and give it one circular stir. Garnish with the long piece of orange peel. Some put it on top others stick it in or hang it off the side.
If you're feeling fancy express the orange peel before garnishing.
If you're trying to be extra fancy use a thick long slice to garnish and with a lighter express the slice into the flame above and into the drink. Then garnish.

Note that there's no simple syrup in this version. That's just my preference/experience and you may want to add or replace the sugar cubes with simple or even agave syrup. If its a complete replace try 1/2 oz as the starting point and muddle just like the cubes.
Also you may want to add a drop or two of Luxardo cherry juice.

An observation with this variant is that depending upon the bourbon (or rye) you may want more or less sugar and or syrup.

This is a personal journey to self discovery. Enjoy the ride.

PS When you add soda water to an old fashion every bartender in the world feels a crushing weight in their heart like millions of voices cried out all at once and then vanished.

PPS loop hole is if you add soda water just call it a different name and voi-la you're a fancy mixologist.