Sorry to hear about this experience @Rena1031! You’ve definitely taken the best steps to extend signal to your Cam. It sounds like there are some walls and distance causing interference in signal here. Sometimes adjusting the placement of the Chime Pro can help, as well as moving appliances, furniture, or electronics that might be interfering with signal along the way. Considering the line of sight for wifi signal will help with avoiding blockers.
While your modem cannot be moved, another potential solution is adding a standalone router and putting your modem in bridge mode to that access point, or using a longer Ethernet to extend reach of the router. I recommend also checking the type of router you have, as an older router model might not perform as well as an updated model. I hope this helps! 