Any% if you are looking for a pretty chill and easy category that is a bit longer and has a a lot of exotic tricks to learn. Free play for a more difficult fast paced category with a lot of hard clips and tricks with no downtime in the run, but much shorter. I wouldn't recommend any other categories till you learn either of those.

are u in the discords for lego speedrunning? if so it would help so you can get up to date info on any% and if you need help right away you can contact runners. Also i agree with wiisuper any% is the way to go or freeplay

I recommend Lego City and New Town if you're looking for ILs as they don't have many hard tricks and have IGT. Going for full game I think any% or free play are both great options.