Can you.... I suppose.
Should you, probably not.
And there you have it, in a nutshell.
It all depends on whether the the extent of your knowledge is figma and XD. Are you qualified to start a business in UI/UX? Are you a designer? If you are, then I apologise for the presumption. If not, there’s a whole lot more to it than making pretty with software.
There are two reasons for not embarking on your suggested route unless you really do know what you are doing; firstly the market is saturated with legions of unqualified people who think it is a cool and easy path to a career. Secondly, there are a lot of good, qualified people out there, who you will be competing against.
Get your all you ducks in a row first. I have assumed you are fairly young and in the early stages of a [potential] career because of the very nature of your question (we’ve seen similar, in various guises a thousand times before).
Again if you are already a professional, qualified designer, I apologise. Your post is not explicit in this regard.
If you give more detailed information, I am sure you will get more detailed help on how to achieve your goals.