There are SO MANY factors that goes into this.
Time played:
Is just time played, it doesn’t matter what you do otherwise (as long as you do something) 5 min will give you 5 min worth of RP/SL no matter what else you did. that being said the activity time does affect this, so if you spend 5 min doing nothing you aren’t going to get much of anything, but 5 min of active playing (getting hit, shooting enemies, capping points, etc) gets you more. if the activity is the same in two matches and the time is the same it will give the same reward.
Action:
Every action has a reward tied to it in some way. same here, the exact same action rewards the same RP/SL every time. Actions against higher BR players does however reward more and actions against lower BR rewards less.
Kills:
Here is where things get interesting. Not only is there a reward for kills based on BR of enemy in relation to your BR, but the “skill bonus” rewards a multiplier to the base RP (it does not include boosters or premium time) so x amount of kills multiplies the total base RP at the end of the game.
Vehicle modifiers:
These are built into the numbers you see at the and of the game and are multipliers applied to a standard reward for every action, these multipliers get bigger the higher BR the vehicle (in general), you can see this multiplier in the stat card of every vehicle.
so lets say the standard for a kill is 50RP for a base BR 1.0 vehicle. once you unlock and play a BR 2.0 you get a 1.5 x multiplier for when using that vehicle so then the base RP would be 75RP per kill.
Example (numbers taken out of thin air as examples as i don’t remember the actual numbers at all):
3 min time gets you 400RP
3 kills get you 200RP (and a 25% bonus)
Random misc actions 1000RP
Total base: 1600RP
With bonus from kills:
1600 + (1600x0.25) = 1600+400 = 2000RP
if you have premium account:
1600 + (1600 x 1 from premium) + (1600x0.25 from skill reward) = 3600RP
if you have premium and a 50% booster:
1600 + (1600 x 1 from premium) + (1600x0.25 from skill reward) + (1600x0.5 from booster) = 1600 + 1600 + 400 + 800 = 4400RP
and so on, so everything is calculated on the base reward and does not stack.
SL is calculated the same way but does not benefit from the skill bonus.
I’m pulling all this from pure memory, i might be wrong in some places so take it with a grain of salt.
Edit:
someone made this document about 7 months ago.
(Thread here)
i missed out on win/loss multipliers and game mode multipliers (but you asked for Realistic specifically so it doesn’t affect it)