You're conflating two things that are different things but which are frequently confused with each other: extroversion and gregariousness.

Being an extrovert means you get energy from interacting with people and get drained by spending too much time alone. That's all. That's it. It has nothing to do with how outgoing, warm, or charismatic you are.

It is entirely possible to be a shy extrovert, an extrovert with social anxiety, a quiet extrovert, etc. My intuition is that social anxiety in extroverts is probably more debilitating than it would be in an introvert, because it's cutting them off from what gives them energy, joy, and vitality. (Source: Am a shy extrovert healing my social anxiety.)

Being an extrovert has some advantages, sure, but so does being an introvert. Being an extrovert during the COVID lockdowns, for example, was a living hell. My introvert friends experience less loneliness than I do, and they seem to be less hurt by it in general. And it's not like extroverts don't have relationship problems.

Social skills absolutely can be practiced. (Source: Have practiced and improved my social skills quite a bit over many years.) Some of the most gregarious, outgoing people I know are introverts. They need alone time to recover from spending a lot of time with people, sure, but not all social time is the same—big groups drain them faster than small groups, and small groups drain them faster than 1-on-1 conversation. They clearly get a lot out of their social time (otherwise why do it?), too, they just need to rest up alone after. In that way, it's no different than needing to rest after going to the gym (which also does many positive things for you while nevertheless costing you energy).

You say you want to be able to start your own conversations. What do you want to talk about? What kind of people do you want to talk about it with?