https://www.radiolabs.com/radio/am-radio-antennas/am-radio-antenna-am-signal-booster/A few years ago I talked to a fellow in your predicament and he was using something similar to this device and liked it. There have been a few variations over the years. It's basically and L-C adjustable tuned circuit. I'm not sure how sharp the tuning (Q) is but you may have to tune it for each station, but maybe you can tune it in the middle. As always, keep it away from metal objects, other wiring , roof flashing, etc.
Look up the patterns of the stations, both day and night if they are directional, and see if they favor your direction, or perhaps have a null to protect some far-off station.
73 de Norm W1ITT