Sounds about right yeah, SAM and RDM are both fairly simple, with RDM being the easiest of the 2, but they both require Stormblood and a lvl 50 and they start at 50 which can be a bit tough for newer players since you kinda want to sit down and read all your skills and stuff. I'd say SAM is easier to play when you're used to the game, but being a melee you have more stuff to dodge, lower GCD to think of your next move and positionals to deal with, so RDM turns out easier in the end I think.
Out of the older classes, MNK is probably the simplest, but it's not that easy. Every attack is a positional and while the rotation is simple, it's not THAT obvious, although you can an unoptimal really easy rotation. Once you learn the rotation however it flows very well and there's no proc to look for or random elements(only your 5pt combo thing that generates automatically and when it's ready it does a ding noise and then you press the button to punch with it during a GCD, nothing hard).
Dragoon rotation is quite a mess and it doesn't help you constantly have to change it as you level up plus the animation lock jumps can be deadly. Blackmage is pretty simple at first but it gets more complicated and endgame BLM damage optimization is super annoying. SMN is also hard to optimize, although iirc the basic rotation isn't that bad, but have to keep track of dots and counters for stuff to line up and what not, plus you have to babysit your pet a little bit(fight specific).
MCH and BRD are pretty intensive gameplay and require paying attention to a bunch of other stuff like dot duration, procs and support abilities(especially on BRD you have to keep track of the tank health and cooldowns to use yours efficiently in the middle of your complicated damage rotation).