Welcome!

Plenty of good company and advice on almost any subject available, should you need it..

Like Thor, I do not use 3D printing or CNC, but they have their uses, where handle twirlers like me cannot compete.

FWIW, when you buy a lathe,you have already found a need for something larger, so the advice still stands, but go for something a bit larger than you think you will need.

Your choice will depend on more than one factor, budget, space etc But you can do quite small work in quite a large lathe.

As a generalisation, alrger lathe will be more rigid and have more features. (Power feeds vare nice to have, especially Cross Feed ) to improve finish Changing to a different thread pitch is quicker with a gearbox, but absolutely vital, than altering bthe changewheel setb up. (And avoids much of the calculation needed that may be needed.. Although therv are usually tables available for many threadfs and lathe arrangements.

What works for a Myford ML7 with a 8 tpi leadscrew will work equally well on a different machine, with a 8 tpi leadscrew, if suitable gears are available..

VFD is nice and easier than changing belts, but a "nice to have" rather than an absolute necessity.

Belt drives tend to be quieter than gear head machine, but yo soon become accustomed to the various featires of the machine that you are operating..

No doubt you will soon become accustomed to handwheel operation on a newer machine to move the Saddle, compared to the less intuitive of the ML1. Just be careful when changing between machines!

Howard.