One picture to understand the difference of hybrid technology

The P0 motor is located on the front-end accessory drive system of the engine. It is linked to the engine through a pulley to realize power generation, engine start and automatic start-stop functions. It does not participate in driving and is widely equipped on pure fuel vehicles, extended-range vehicles, plug-in hybrid vehicles and other models

The P1 motor is installed at the crankshaft end of the engine and integrated into the engine through the crankshaft as a rotor. It plays the role of generator, starter motor, inverter for kinetic energy recovery, and auxiliary power. It is widely used in 48V mild hybrid vehicles. However, since P1 cannot drive the vehicle alone like P0, its help to fuel economy is very limited

In the P2 architecture, the motor can drive the vehicle alone. The engine does not work when kinetic energy is recovered. At the same time, the continuation of the transmission ratio does not require too much torque, so the motor can be made smaller and save costs, and the whole vehicle also has better fuel economy. The four-wheel drive front axle of the longitudinal rear-wheel drive hybrid system off-road vehicles such as Wrangler, Prado, Tank 500Hi4-T basically adopts the P2 architecture

The P3 motor is located at the end of the gearbox and is connected to the engine by a belt, gear or coaxially. Compared with P2, P3 motor can be connected in series with the engine to drive the half shaft, or it can skip the transmission and drive the half shaft directly through a set of reducers. Most front-wheel drive plug-in hybrid vehicles basically use P1 and P3 architectures. Representative models include BYD DM-i, Lynk & Co 06EMP, Changan Qiyuan A05 and other models.
P4 motor has no direct connection with the engine and transmission. It is usually arranged on the rear axle or as a wheel-side motor to provide a rear drive source for hybrid vehicles. Since there is no mechanical connection between the P4 architecture motor and the engine, the front and rear axles are driven independently, the power distribution efficiency is higher, and the four-wheel drive stability and cornering performance are better. Volvo T8, Toyota Intelligent Electric Hybrid Dual Engine Four-wheel Drive Series, Great Wall Haval Raptor Hi4, Xiaolong Hi4 and other models all have P4 architecture. In fact, BYD Yangwang U8 is also a P4 architecture model that has broken away from the engine-driven extended-range four-wheel side motor.

Finally
Technological innovation is endless. P0-P4 is no longer a separate and unrelated entity. In order to provide better vehicle performance, many brands are actively exploring the hybrid utilization technology of different architectures. It is difficult for us to define it with a single or only two architectures.
For example, BYD DM-i/p, Geely Thor/EMP, Toyota electric hybrid dual-engine four-wheel drive, Great Wall Hi4, Chery Kunpeng, etc., all integrate different motor architectures such as P1, P2/P3, and P4. Hybrid vehicles are moving towards a more economical, reliable and comfortable direction.