You have two directions you can go
1) your favorite yeast which will stop as 14 or 15% ABV > when fermented dry add alcohol to stop the fermentation and sweeten as desired. Also consider adding glycerine.
2 a step feeding process with 1118 or similar yeast capable of tolerating 18% ABV. At some point the yeast will have reached it’s limit and you will find that the last sugar addition isn’t going away, ,,, and it will taste sweet.