Maybe I'm at a sweet spot but 35-37 have been the levels I've done since 1.19...
Before 1.19 I was doing ok but it was really frustrating mainly because xp would max out at 255 for a mob 10 levels above me and that was the xp cap. My pug could easily kill stuff 12-13 levels above but it was a waste.
I come back and find I can kill a mob 3-4 levels above me and get 600xp! So I've been chaining Pterocs in Coerthas and getting 2500xp in like 6 minutes - chain 3/4 almost everytime with downtime only as I run to find another nearby group. The xp is flying and its a lot of fun. *whips out calculator* That's over 20k/hr easy!
With a good EVA build, alternating Featherfoot and Light Strike, I'm always getting multiple Haymakers off which is completely killer. Sometimes I throw a Jarring Strike in since you can do both on the same miss. Recently I leveled CON for some of its spells thinking it would help but I don't even use them. And when I got Second Wind II at 36, I have like zero downtime.
Sometimes I hear people whining about it being difficult to solo in ffxiv, while I'm sure those days are ahead, right now its a blast! Grab your PUG and go kill puk/pterocs. Nanawa has some starting at 30ish, and prior to that at 25 you can do Cedarwood. Switch to Coerthas at 34/35. I'll probably be here for one or two more levels and then find the next spot.