There are only a handful of flavors that can really be subbed. And subbing anything will always change the recipe.

If you're subbing vendors, then you're not using the same flavor.

I don't really do subbing when I'm hoping to make someone else's recipe, but I definitely do play with parts of other people's recipes + customize them more to my liking. I do a lot of single flavor testing so that helps me better know what options may work in a recipe if I do need to sub, or I ask more knowledgeable mixers here or on the DIY discord. DIY Discord can offer lots of help in real time, it's great. If I do want to sub in a recipe, I always try to send the mixer a message asking if they think certain subs would be okay.

TFA Bavarian Cream is a super useful, versatile flavor that's probably worth getting imo, if your example is specific of course :)

Subbing flavors isn't necessarily a bad thing if you enjoy the flavor your subbing with. It won't be the same recipe you were making, but it might still be a good recipe in the end.

Everyone covers the gist, but you can work out "iffy formulas". e.g., look at the recommended starting dosage for the two, and mentally adjust what the recipes are using. Always remember you can add but can't take away.

Flavourart is known for having much stronger flavors than others, so as an example: Recipe calls for Capellas Bazinga at 6%, while most recommendations call for Cap Bazinga to be at 7-10% as a single flavor. So you know they want it strong in the mix, but not necessarily the strongest flavor. You have Flavourart Bazinga, which is recommended to start at 4% as single flavor, so probably best to start at 1.5-2% with a tester, but probably more like 1.5%. Worst case you aren't tasting what you want in the mix and add more.

I'd listen to everyone about them not being interchangeable, but you're usually getting something not as good as it can be and not unvapable. Some differences are the DX and V2 versions of flavorings with butyric acids substituted for acetoins and such. Some people just get hit by the smell and taste of vomit with many of them. The same thing happens with Hershey's chocolate here. It isn't every version for most, but some it hits hard.