I was out of it for 10 years after I joined the military and being busy after 9-11 etc....
I was surprised to see LOTS of kit development in a hobby I thought was dead.
I would recommend older Tamiya kits, like the SU-122 assault gun. It is a simple kit (Was 1976 or 77 mold I think) and is a great way to get back into the swing of things.
After I felt confident I dove right into a newer CyberHobby/Dragon kit with the smart link tracks. WOW, a bit too much to bite off so I did the tank and held off on the tracks till I gained more experience later on how to do them (youtube).
You will find the Dragon kits intimidating as there are so many sprues packed into the model box. But just do one by one and research the kit for a review, some of the reviews point out errors in the instructions that may save a headache!
I have not gotten into painting and weathering, just building again for fun and to get back into it. Once I feel confident and up to the task I will tackle painting. And there are SO many new techniques out there now to make great looking stuff.
While small, the hobby really has become a lot better.
Personally I think the biggest improvement you will see is Dragons GEN2 figures, wow, the molding is light years ahead of even 1990's molds.