Just getting an extension cable and placing your antenna outside up high as possible should greatly increase your antenna capability. Even if it's a stock antenna.

I'm sure there's better ones out there but these cables haven't steered me wrong yet.

TRENDnet Low Loss RP-SMA Male to RP-SMA Female Antenna Cable, 6 m (19.6 ft.), 3.0 dB Max Signal Loss, TEW-L106 black https://www.amazon.com/dp/B06ZXRWLXQ/ref=cm_sw_r_apan_glt_fabc_YSKVV708CWBN2Y0PXBXV?_encoding=UTF8&psc=1

TRENDnet Low Loss RP-SMA Male to RP-SMA Female Antenna Cable, 6 m (19.6 ft.), 3.0 dB Max Signal Loss, TEW-L106 https://www.amazon.com/dp/B06ZXRWLXQ/ref=cm_sw_r_sms_apap_roAe52Sumoq71

This is what I used when extending my WiFi. Little longer than you need (looks like the have a 6.5 ft version) but should get you on the right path! My panel is outside I actually ran up the wall and into the attic as close as possible to where my network equipment is