Really don´t go paladin for STR, you will be really disappointed
Chaplain would bring more constant damage even for your grindring. Conviction + Smite is a nice dmg meanwhile you go buffing in a party, yes, but for that you really don´t need to go STR, Smite has a great atk power already. Going Chaplain you can go Cleric 2 which helps healing in PVE groups.
I’m a Paladin with this setup (Cleric 1 Priest 3 Pala 3) and tested the STR build. Really not a good one. I´m going CON / SPR mainly for support + Smite & Conviction for dmg, using elemental atks in headgear and arde or karacha dagger, you can do 20k damage with Smite in one hit in Demon type for example in high levels (50% passive attribute included). Considering it has overheat 2 and 9s cd is not bad meanwhile you support the party. The problem is not having Cleric 2 for healing. Most parties will not want you for that 