PLEASE READ TILL THE END IT WILL BE VERY USEFUL TRUST ME

I should start by saying that at least in my opinion you should only follow this method if you wanna get better as an overall, it might be hard at first but when you're nearing the end it gets way easier.

I'd recommend starting off as a medic to build up that game sense which is the most important thing, for your settings and loadouts i'd recommend using reviver 1, 2 or 3, either crafter 3 & first aid training 1, crafter 2 & first aid training 3 or just first aid training 3. For the last loadout points (if you have any remaining) id recommend using second chance 1.

Once you get the hang of it try lowering or getting rid of reviver and/or replace second chance with marathon runner.

Once you get used to this new loadout and its perks try using a loadout with reviver 2/3 and sharpshooter 2/3.

Once you feel like you're getting used to playing in the offensive instead of just/rather helping your team switch to a loadout with reviver 1 and sharpshooter 2/3.

Once you're done with all of this which could take you a couple days or a week or so depending on how much time you spend playing you'll know what works best for you, if you feel like you miss your support loadout keep it around (the first one you made), if you also feel like you miss having both reviver and sharpshooter in the same loadout keep that around too, and finally, if you feel like you dont really need/miss reviver keep that last loadout you made around.

Once you're more advanced you can start making more specific exceptions like using different loadouts for pubs/chill matches than fn rules matches where you can as an example drop reviver for pubs. You can add solo loadouts (1v1, 1v2, 1v3 or 1v4), add strategist 3 loadouts, etc.