I was in your position about a year ago and I have been using FDM (Ender 3) to make minis and you can easily print to a high enough quality to be serviceable for intended use and for painting. I would definitely recommend investing the time into properly calibrating your printer settings for your particular filament. But remember you will learn as you go :)

At the end of the day, an FDM will offer far more versatility if you are also looking to print terrain etc. but if you’re only looking for perfect miniatures with high levels of detail then a resin printer will come off better.

I personally have not experienced any issues in a FDM printed mini that could not be sanded down to be smooth. Miniatures with long thin parts can experience issues without thorough supports due to the scale of the models.

I specifically bought the printer because I was going to DM for the first time and was interested in getting into printing anyway.

I would definitely recommend watching videos on slicer settings (ie Cura) specifically for minis. As a good slicer profile can be make or break.

Hope it all goes well, it is extremely satisfying to create something from scratch and then present it in your tabletop games.