The type of insert is dictated by the type of holder and the insert pocket, so if you are using 80 degree insert with a neutral insert pocket then you are looking primarily at CCxT type. Not sure about what a CCMG insert type is, looks like limited to YG inserts, but you would not use CNMG inserts in a neutral rake holder. So typically for ferrous metals you would use a molded insert which is more resistant to intermittent cuts/rough deep cutting because the edge profile is thicker and typically will have less positive edge rake. If you are cutting softer materials such as aluminum, cast iron, brass, plastic, etc. then you typically would want a ground edge profile with more positive edge rake, so CCGT. The latter is usually uncoated, highly polished and may have some chip control features. I typically use a 32.51 type insert, a 32.52 has a larger nose profile used for deeper cuts/heavier cuts. Typically I get 3-6 months out of an insert, but depends on the use/material.
I find that the cheaper generic type inserts like Cobra do not last, so I try to stick with more mainstream manufactures. The biggest problem these days is that most of what comes out of Asia is counterfeit.
On the type of insert/coatings it is often dependent on the materials you are primarily using it for. If you do harder metals or stainless then you may want a specific insert type (profile and chip breaker) /coating of insert indicated for those metals. If you do a wide range of metals then I would focus on two type of inserts for a particular insert shape as follows:
Examples below that I use with good results:
Uncoated, ground edge polished inserts
KORLOY OR CERAZTIZIT CCGT 09T304-AK H01 CCGT32.51-AK
https://www.ebay.com/itm/CERATIZIT-carbide-inserts-CCGT-09T304FN-25P-H210T-NEW-10pcs/183173370054
https://www.ebay.com/itm/New-KORLOY...-CNC-Carbide-Insert-10PCS-in-BOX/122617092912
Molded coated insets suitable for a wide range of ferrous metals
ISCAR CCMT 09T304-SM IC907 CCMT32.51
https://www.ebay.com/itm/CCMT-3-1-SM-IC907-ISCAR-10-INSERTS-FACTORY-PACK/192526290854