Withoud his Df he has no gear second, third or fourth.
Soo no, withoud his DF he is not that strong, specialy considering his "enchanced stats" comes from his gears.
Zoro used a sword to cut a chimney in W7 while Luffy broke a city apart with his raw strength.
Luffy went from being 1.25-1.5 times as strong to nearly twice as strong with the gears, now he has other advantages like penetration haki/ future sight that catapult him in base, because both of those are bigger upgrades than g2,g3, and arguably g4.
G2 is a slightly buffed soru, at this point everyone is using some sort of soru level movement speed in the power creep, this just lets him be the fastest in the room using physical power, lets him do freaky things like dodge explosions from the epicenter, lets him perform the feat that was signposted as twice as powerful as Sanji/Zoro's feat against the pacifista., lets him outmaneuver a 2vs1 vs. tobi roppo level threats.
G3 is a massive boost to offensive power, and is one of the things that puts him in a higher tier than his crew, able to incapacitate page one in one shot without using 2nd level ryuo or even barrier haki.