66 yo female road bike rider needs advice on THE BEST CLIMBING components/groupsets available!
Also consider some help from an ebike motor.  It may not be fully to your preference, but the small push on the steepest bits will help save your knees and your heart.

This may go against the "purity" ethos that some cyclists value, but at the end of the day its all about riding.

There are retrofit wheel kits for existing bikes, or a bolt-on mid drive, or a much more subtle bottom bracket booster like that woman used in the CX competition (apparently by mistake)

A higher end solution would be to get an electric road bike where the motor is integrated into the frame at the bottom bracket, and batteries are stored in the downtube rather than bolted onto your water bottle mounts or out the back on a parcel rack.  But that's much more cost.