Do all factions have the same strengths and where can I see their doctrine details?

No. Every faction has different strengths.

For example:

• Space Marines: Unlock Buffs that benefit tactical usage of units.

• Astra Militarum: Unlock buffs that benefit defense and mobilization.

• Orks: Unlock Buffs that benefit Speed and Horde size.

• Chaos Space Marines: Unlock Buffs that benefit an aggressive expansion

To see detailed information, open the Doctrine menu and:

• Tap the (i) button in the Doctrine overview to view the path summary.

• Tap individual doctrines to see their specific bonuses before unlocking them.