5g Gateway with 2 bars, outside of home 5 bars with cell, inside 1 bar, what do you recommend , wifi extender or external antennas?

Hi ,

just wondering what would be best solution to move forward. Got new 5G Gateway a week ago. Tried different places and heights. Best spot is 2 bars. With cellphone inside house 1 bar and outside by door entrance full 5 bars. So my question with seeing all your comments. Should I go with waveform external antenna or try wifi extender?