You only learn by hard experience! Many of us here have flown many types of singles and twins in bad weather summer, winter day night!
Many of those aircraft have been pretty basic and that develops your skills and situational awareness in a way that no pilot assist, all singing and dancing aircraft could possibly do.
An aircraft that makes you work and have to think for yourself means that when you do fly aircraft with all the pilot assist aids the two will compliment each other rather than one making up for a lack of skills of the pilot!
Even if you have money to burn I would still recommend that route too!
Pace