Newbie collector question- Studio Series 86 vs. MTMTE toys?

I’m a new collector and just started picking up figures over the past few months. I’m mainly focused on G1 accurate characters from the cartoon and the 1986 movie, so I’ve been buying some Studio Series 86 figures from Amazon and eBay.

Recently, though, I’ve seen some figures at Target that don’t have the 86-## numbering, which got me wondering what’s the difference between Studio Series 86 and MTMTE releases?

For example, I recently picked up Hot Rod (the one with the fishing rod), but I noticed it looks really similar to Studio Series 86-04 Hot Rod. Is it basically the same figure with different accessories or paint, or is there more to it? Am I missing anything by not having the 86-04 version?

Also, are there any other Transformers lines I should be watching for? I’ve heard the War for Cybertron line is pretty popular.

Thanks in advance for any recommendations!